Efficacy of ultrasound-guided transversus abdominis plane blocks for post-cesarean delivery analgesia: a double-blind, dose-comparison, placebo-controlled randomized trial

Intrathecal Morphine and Effect on Opioid Consumption and Functional Recovery after Pancreaticoduodenectomy

BACKGROUND

Single-shot intrathecal morphine (ITM) is an effective strategy for postoperative analgesia, but there are limited data on its safety, efficacy, and relationship with functional recovery among patients undergoing pancreaticoduodenectomy.

STUDY DESIGN

This was a retrospective review of patients undergoing pancreaticoduodenectomy from 2014 to 2020 as identified by the institutional NSQIP Hepato-pancreato-biliary database. Patients were categorized by having received no spinal analgesia, ITM, or ITM with transversus abdominus plane block (ITM+TAP). The primary outcomes were average daily pain scores from postoperative days (POD) 0 to 3, total morphine equivalents (MEQ) consumed over POD 0 to 3, and average daily inpatient MEQ from POD 4 to discharge. Secondary outcomes included the incidence of opioid related complications, length of stay, and functional recovery.

RESULTS

A total of 233 patients with a median age of 67 years were included. Of these, 36.5% received no spinal analgesia, 49.3% received ITM, and 14.2% received ITM+TAP. Average pain scores in POD 0 to 3 were similar by mode of spinal analgesia (none [2.8], ITM [2.6], ITM+TAP [2.3]). Total MEQ consumed from POD 0 to 3 were lower for patients who received ITM (121 mg) and ITM+TAP (132 mg), compared with no spinal analgesia (232 mg) (p < 0.0001). Average daily MEQ consumption from POD 4 to discharge was lower for ITM (18 mg) and ITM+TAP (13.1 mg) cohorts compared with no spinal analgesia (32.9 mg) (p = 0.0016). Days to functional recovery and length of stay were significantly reduced for ITM and ITM+TAP compared with no spinal analgesia. These findings remained consistent through multivariate analysis, and there were no differences in opioid-related complications among cohorts.

CONCLUSIONS

ITM was associated with reduced early postoperative and total inpatient opioid utilization, days to functional recovery, and length of stay among patients undergoing pancreaticoduodenectomy. ITM is a safe and effective form of perioperative analgesia that may benefit patients undergoing pancreaticoduodenectomy.

The Role of Regional Anesthesia in the Development of Chronic Pain: a Review of Literature

Purpose of Review

The acute management of pain using regional anesthesia techniques may prevent the development of persistent postsurgical pain (PPP), ultimately improving patient outcomes and enhancing overall quality of life in postsurgical patients. The purpose of this review is to describe the current literature regarding the role of regional anesthesia techniques in the perioperative setting to address and prevent PPP.

Recent Findings

Data was collected and analyzed using results from randomized controlled studies stratified into categories based on different surgical subspecialties. Conclusions were drawn from each surgical category regarding the role of regional anesthesia and/or local analgesia in acute and chronic pain management on the long-term results seen in the studies analyzed.

Summary

Preoperative consultations and optimized perioperative analgesia using regional anesthesia and local analgesia play a fundamental role preventing and treating postoperative pain after many types of surgery by managing pain in the acute setting to mitigate the future development of PPP. Additional studies in different surgical subspecialties are needed to confirm the role regional anesthesia plays in chronic postsurgical pain (CPSP) prevention.

Postoperative Analgesic Effectiveness of Peripheral Nerve Blocks in Cesarean Delivery: A Systematic Review and Network Meta-Analysis

The purpose of this systematic review and network meta-analysis was to determine the analgesic effectiveness of peripheral nerve blocks (PNBs), including each anatomical approach, with or without intrathecal morphine (ITMP) in cesarean delivery (CD). All relevant randomized controlled trials comparing the analgesic effectiveness of PNBs with or without ITMP after CD until July 2021. The two co-primary outcomes were designated as (1) pain at rest 6 h after surgery and (2) postoperative cumulative 24-h morphine equivalent consumption. Secondary outcomes were the time to first analgesic request, pain at rest 24 h, and dynamic pain 6 and 24 h after surgery. Seventy-six studies (6278 women) were analyzed. The combined ilioinguinal nerve and anterior transversus abdominis plane (II-aTAP) block in conjunction with ITMP had the highest SUCRA (surface under the cumulative ranking curve) values for postoperative rest pain at 6 h (88.4%) and 24-h morphine consumption (99.4%). Additionally, ITMP, ilioinguinal-iliohypogastric nerve block in conjunction with ITMP, lateral TAP block, and wound infiltration (WI) or continuous infusion (WC) below the fascia also showed a significant reduction in two co-primary outcomes. Only the II-aTAP block had a statistically significant additional analgesic effect compared to ITMP alone on rest pain at 6 h after surgery (−7.60 (−12.49, −2.70)). In conclusion, combined II-aTAP block in conjunction with ITMP is the most effective post-cesarean analgesic strategy with lower rest pain at 6 h and cumulative 24-h morphine consumption. Using the six described analgesic strategies for postoperative pain management after CD is considered reasonable. Lateral TAP block, WI, and WC below the fascia may be useful alternatives in patients with a history of sensitivity or severe adverse effects to opioids or when the CD is conducted under general anesthesia.

Efficacy of regional blocks or local anaesthetic infiltration for analgesia after caesarean delivery: a network meta-analysis of randomised controlled trials

Caesarean delivery is common and can cause severe postoperative pain but injection of local anaesthetic at various sites for regional blocks or local anaesthetic infiltration may reduce this. We aimed to compare and rank these sites. We searched PubMed, Google Scholar, EMBASE and CENTRAL to June 2021 for randomised controlled trials and performed a random-effects Bayesian model network meta-analysis. The primary outcome was dose of parenteral morphine equivalents in the first 24 postoperative hours. We used surface under cumulative ranking probabilities to order techniques. We analysed 114 trials (8730 participants). The ordered mean (95% credible interval) reduction in morphine equivalents, from 34 mg with placebo, were as follows: ilio-inguinal 15 (1-32) mg; ilio-inguinal-iliohypogastric 13 (6-19) mg; transversalis fascia 11 (4-26) mg; erector spinae 11 (10-32); transverse abdominis 9 (4-13) mg; wound catheter infusion 8 (2-15) mg; quadratus lumborum 8 (1-15) mg; wound infiltration 8 (2-13) mg; and no intervention -4 (-10 to 2) mg. Ordered efficacies for injection sites were different for other relevant outcomes, including pain (to 4-6 h and to 24 h) and time to rescue analgesia: there was no single preferred route of injection. The ordered mean (95% credible interval) reduction in dynamic pain scores (0-10 scale) at 24 h compared with placebo were as follows: wound infusion 1.2 (0.2-2.1); erector spinae 1.3 (-0.5 to 3.1); quadratus lumborum 1.0 (0.1-1.8); ilio-inguinal-iliohypogastric 0.6 (-0.5 to 1.8); transverse abdominis 0.6 (-0.1 to 1.2); wound infiltration 0.5 (-0.3 to 1.3); transversalis fascia -0.8 (-3.4 to 1.9); ilio-inguinal -0.9 (-3.6 to 1.7); and no intervention -0.8 (-1.8 to 0.2). We categorised our confidence in effect sizes as low or very low.

Analgesic efficacy of ultrasound-guided transversus abdominis plane block after cesarean delivery: A systematic review and meta-analysis

PURPOSE

The meta-analysis is aimed to further access the analgesic efficacy of ultrasound-guided transversus abdominis plane (USG-TAP) block after cesarean section (CS).

METHODS

Electronic databases were searched for eligible studies. Primary objectives were pain-related outcomes. Weighted mean differences (WMDs) or standardized mean differences (SMDs), as well as risk ratios (RRs) with 95% confidence intervals (CIs), were used to calculate estimates. Subgroup analyses were done based on whether USG-TAP blocks were performed with long-acting intrathecal opioids (ITO).

RESULTS

A total of 17 studies were included. When compared with control groups (placebo or no blocks), USG-TAP block resulted in lower cumulative opioid consumption at 6 h (WMD: -8.32; 95% CI: -14.86, -1.79), 12 h (WMD: -10.75; 95% CI: -20.93, -0.57), and 24 h (WMD: -12.71, 95% CI: -21.28, -4.14). No significant differences were demonstrated among dynamic or resting pain scores. Patients in USG-TAP groups needed longer time to request first analgesic (WMD: 3.56; 95% CI: 1.43, 5.68) and showed a lower requirement of opioid rescue analgesia for breakthrough severe pain during 24 h (RR: 0.40; 95% CI: 0.18, 0.86). Subgroup analyses showed USG-TAP blocks did not afford additional benefit in the presence of intrathecal morphine. Also, reduced need for antiemetics after CS and higher maternal satisfaction were provided by USG-TAP blocks.

CONCLUSION

USG-TAP block can provide significantly effective analgesia for patients who underwent CS in the absence of long-acting ITO and therefore are worth promoting in the setting of long-acting ITO being unfeasible.

Regional Anesthesia Abdominal Blocks and Local Infiltration After Cesarean Delivery: Review of Current Evidence

PURPOSE OF REVIEW

In this review, we discuss surgical infiltration and various abdominal wall blocks, including transversus abdominis plane (TAP) block and quadratus lumborum blocks, and review the literature on the evidence behind these approaches and analgesia for cesarean delivery (CD).

RECENT FINDINGS

Adequate pain management in the parturient following CD is important to facilitate early ambulation and neonatal care while also improving patient satisfaction and decreasing hospital length of stay. Neuraxial opioids have been a mainstay for postoperative analgesia; however, this option may not be available for patients undergoing emergency CD and have contraindications to neuraxial approaches, refusing an epidural or spinal, or with technical difficulties for neuraxial placement. In such cases, alternative options include a fascial plane block or surgical wound infiltration. The use of regional blocks or surgical wound infiltration is especially recommended in the parturient who does not receive neuraxial opioids for CD. Adequate postoperative analgesia following CD is an important component of the overall care of the parturient as it helps facilitate early mobilization and improve patient satisfaction. In conclusion, the use of abdominal fascial plane blocks or surgical wound infiltration is recommended in the parturient who does not receive neuraxial opioids for CD.

European Society of Anaesthesiology and Intensive Care Guidelines on peri-operative use of ultrasound for regional anaesthesia (PERSEUS regional anesthesia): Peripheral nerves blocks and neuraxial anaesthesia

Nowadays, ultrasound-guidance is commonly used in regional anaesthesia (USGRA) and to locate the spinal anatomy in neuraxial analgesia. The aim of this second guideline on the PERi-operative uSE of UltraSound (PERSEUS-RA) is to provide evidence as to which areas of regional anaesthesia the use of ultrasound guidance should be considered a gold standard or beneficial to the patient. The PERSEUS Taskforce members were asked to define relevant outcomes and rank the relative importance of outcomes following the GRADE process. Whenever the literature was not able to provide enough evidence, we decided to use the RAND method with a modified Delphi process. Whenever compared with alternative techniques, the use of USGRA is considered well tolerated and effective for some nerve blocks but there are certain areas, such as truncal blocks, where a lack of robust data precludes useful comparison. The new frontiers for further research are represented by the application of USG during epidural analgesia or spinal anaesthesia as, in these cases, the evidence for the value of the use of ultrasound is limited to the preprocedure identification of the anatomy, providing the operator with a better idea of the depth and angle of the epidural or spinal space. USGRA can be considered an essential part of the curriculum of the anaesthesiologist with a defined training and certification path. Our recommendations will require considerable changes to some training programmes, and it will be necessary for these to be phased in before compliance becomes mandatory.

Quadratus lumborum block vs. transversus abdominis plane block for caesarean delivery: a systematic review and network meta-analysis. Anaesthesia 2020;76:393-403. [PMID: 32621529 DOI: 10.1111/anae.15160]

Caesarean delivery is the most commonly performed inpatient surgical procedure globally. Pain after caesarean delivery is moderate to severe if not adequately treated, and is a primary anaesthetic concern for patients. Transversus abdominis plane and quadratus lumborum blocks are fascial plane blocks that have the potential to improve analgesia following caesarean delivery. Although proponents of the quadratus lumborum block suggest that this technique may provide better analgesia compared with transversus abdominis plane block, there are limited data directly comparing these two techniques. We, therefore, performed a systematic review and network meta-analysis to compare transversus abdominis plane and quadratus lumborum block approaches, seeking randomised controlled trials comparing both techniques to each other, or to control, with or without intrathecal morphine. In all, 31 trials with 2188 patients were included and our primary outcome, the cumulative intravenous morphine equivalent consumption at 24 h, was reported in 12 trials. In the absence of intrathecal morphine, transversus abdominis plane and quadratus lumborum blocks were equivalent, and both were superior to control (moderate-quality evidence). In the presence of intrathecal morphine, no differences were found between control, transversus abdominis plane and quadratus lumborum blocks (moderate-quality evidence). Similar results were found for resting and active pain scores at 4-6 h, 8-12 h, 24 h and 36 h, although quadratus lumborum block was associated with lower pain scores at 36 h when compared with transversus abdominis plane block (very low-quality evidence). However, transversus abdominis plane block was associated with a reduced incidence of postoperative nausea and vomiting (moderate-quality evidence) and sedation when compared with inactive control following intrathecal morphine administration (low-quality evidence). There are insufficient data to draw definitive conclusions, but transversus abdominis plane and quadratus lumborum block appear to be superior to control in the absence of intrathecal morphine, but provide limited additional benefit over inactive control when intrathecal morphine is also used.

Transversus Abdominis Plane Block

In this narrative review article, the authors discuss the anatomy, nomenclature, history, approaches (posterior vs. lateral vs. subcostal), techniques, pharmacology, indications, and complications of transversus abdominis plane blocks, as well as possible alternative truncal blocks.

Despite the scarcity of evidence and contradictory findings, certain clinical suggestions can nonetheless be made. Overall transversus abdominis plane blocks appear most beneficial in the setting of open appendectomy (posterior or lateral approach). Lateral transversus abdominis plane blocks are not suggested for laparoscopic hysterectomy, laparoscopic appendectomy, or open prostatectomy. However, transversus abdominis plane blocks could serve as an analgesic option for Cesarean delivery (posterior or lateral approach) and open colorectal section (subcostal or lateral approach) if there exist contraindications to intrathecal morphine and thoracic epidural analgesia, respectively.

Future investigation is required to compare posterior and subcostal transversus abdominis plane blocks in clinical settings. Furthermore, posterior transversus abdominis plane blocks should be investigated for surgical interventions in which their lateral counterparts have proven not to be beneficial (e.g., laparoscopic hysterectomy/appendectomy, open prostatectomy). More importantly, because posterior transversus abdominis plane blocks can purportedly provide sympathetic blockade and visceral analgesia, they should be compared with thoracic epidural analgesia for open colorectal surgery. Finally, transversus abdominis plane blocks should be compared with newer truncal blocks (e.g., erector spinae plane and quadratus lumborum blocks) with well-designed and adequately powered trials.

A review of peripheral nerve blocks for cesarean delivery analgesia

Peripheral nerve blocks have a unique role in postcesarean delivery multimodal analgesia regimens. In this review article, options for peripheral nerve blocks for cesarean delivery analgesia will be reviewed, specifically paravertebral, transversus abdominis plane, quadratus lumborum, iliohypogastric and ilioinguinal, erector spinae, and continuous wound infiltration blocks. Anatomy, existing literature evidence, and specific areas in need of future research will be assessed. Considerations for local anesthetic toxicity, and for informed consent for these modalities in the context of emergency cesarean deliveries, will be presented.

Laparoscopic-Guided Transversus Abdominis Plane (TAP) Block as Part of Multimodal Analgesia in Laparoscopic Roux-en-Y Gastric Bypass Within an Enhanced Recovery After Surgery (ERAS) Program: a Prospective Randomized Clinical Trial

BACKGROUND

Despite the ultrasound guidance of transversus abdominis plane (TAP) blocks has allowed greater precision of needle placement in the desired tissue plane, visualization of the abdominal wall muscles can be hindered by morbid obesity and could lead to failed regional anesthesia. The aim of this study was to assess the feasibility and effect of laparoscopic-guided TAP block in patients undergoing Roux-en-Y gastric bypass and to compare it with port-site infiltration.

PATIENTS AND METHODS

A prospective randomized clinical trial was performed. Patients were randomized into two groups: patients undergoing laparoscopic-guided TAP (TAP-lap) and patients undergoing port-site infiltration (PSI). Pain quantification as measured by visual analogic scale (VAS) and morphine needs during the first 24 h were evaluated.

RESULTS

One hundred and forty patients were included, 70 in each group. The mean operation time was 83.3 + 15.6 min in TAP-lap and 80.5 + 14.4 min in PSI (NS). The mean postoperative pain, as measured by VAS, 24 h after surgery was 16.8 + 11.2 mm in PSI and 10 + 8.1 mm in TAP-lap (p = 0.001). Morphine rescues were necessary in 13.2% in PSI and 2.9% in TAP-lap (p = 0.026). The mean hospital stay was 2.1 + 1.2 days in TAP-lap and 2.9 + 1.3 days in PSI (p = 0.019). Hospital discharge during the first 48 h after surgery was possible in 52.9% of the patients in PSI and 71% in TAP-lap (OR 4.75; 95% CI 2.1-10.8; p = 0.029).

CONCLUSION

Laparoscopic-guided TAP block can reduce postoperative pain, opioid needs, and hospital stay, when compared with port-site infiltration with the same anesthetic drug, without increasing operation time.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03203070.

Local anesthetics and regional anesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children: A Cochrane systematic review and meta-analysis update

BACKGROUND

Regional anesthesia may mitigate the risk of persistent postoperative pain (PPP). This Cochrane review, published originally in 2012, was updated in 2017.

METHODS

We updated our search of Cochrane CENTRAL, PubMed, EMBASE and CINAHL to December 2017. Only RCTs investigating local anesthetics (by any route) or regional anesthesia versus any combination of systemic (opioid or non-opioid) analgesia in adults or children, reporting any pain outcomes beyond three months were included. Data were extracted independently by at least two authors, who also appraised methodological quality with Cochrane 'Risk of bias' assessment and pooled data in surgical subgroups. We pooled studies across different follow-up intervals. As summary statistic, we reported the odds ratio (OR) with 95% confidence intervals and calculated the number needed to benefit (NNTB). We considered classical, Bayesian alternatives to our evidence synthesis. We explored heterogeneity and methodological bias.

RESULTS

40 new and seven ongoing studies, identified in this update, brought the total included RCTs to 63. We were only able to synthesize data from 39 studies enrolling 3027 participants in a balanced design. Evidence synthesis favored regional anesthesia for thoracotomy (OR 0.52 [0.32 to 0.84], moderate-quality evidence), breast cancer surgery (OR 0.43 [0.28 to 0.68], low-quality evidence), and cesarean section (OR 0.46, [0.28 to 0.78], moderate-quality evidence). Evidence synthesis favored continuous infusion of local anesthetic after breast cancer surgery (OR 0.24 [0.08 to 0.69], moderate-quality evidence), but was inconclusive after iliac crest bone graft harvesting (OR 0.20, [0.04 to 1.09], low-quality evidence).

CONCLUSIONS

Regional anesthesia reduces the risk of PPP. Small study size, performance, null, and attrition bias considerably weakened our conclusions. We cannot extrapolate to other interventions or to children.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children

BACKGROUND

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews.

SELECTION CRITERIA

We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE.

MAIN RESULTS

In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 39 studies, enrolling a total of 3027 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution.

AUTHORS' CONCLUSIONS

We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Clinical analgesic efficacy of dexamethasone as a local anesthetic adjuvant for transversus abdominis plane (TAP) block: A meta-analysis

BACKGROUND

Perineural dexamethasone has been shown to prolong the duration of local anesthetic (LA) effect in regional anesthesia; however, the use of perineural dexamethasone as an adjuvant to to the transversus abdominis plane (TAP) block remains controversial. This meta-analysis sought to assess the efficacy of dexamethasone in prolonging the TAP block and enhancing recovery after abdominal surgery.

METHODS

We identified and analyzed 9 RCTs published on or before September 30, 2017, regardless of the original language, after searching the following 6 bibliographic databases: PubMed, EMBASE, Medline, Springer, Ovid, and the Cochrane Library. databases. These studies compared the effects of perineural dexamethasone mixed with local anesthetic versus local anesthetic alone in the TAP block. The Cochrane Collaboration's Risk of Bias Tool was used to evaluate the methodological quality of each RCT. The primary outcomes were the time until the first request for postoperative analgesics and the analog pain scores at 2, 6, 12, and 24 h after surgery. The secondary outcomes were the analgesic consumption and the incidence of nausea and vomiting on the first day after surgery. We used Trial Sequential Analysis (TSA) to control for random errors.

RESULTS

Perineural dexamethasone prolonged the duration of LA effect in the TAP block [mean difference (MD): 2.98 h; 95% confidence interval (CI): 2.19 to 3.78] and reduced analog pain scores at 2 h [MD: -1.15; 95% CI: -2.14 to -0.16], 6 h [MD: -0.97; 95% CI: -1.51 to -0.44], and 12 h [MD: -0.93; 95% CI: -1.14 to -0.72] postoperatively. Furthermore, the use of perineural dexamethasone was associated with less analgesic consumption [standard mean difference: -1.29; 95% CI: -1.88 to -0.70] and a lower incidence of nausea and vomiting [odds ratio: 0.28; 95% CI: 0.16 to 0.49] on the first day after surgery.

CONCLUSION

Dexamethasone prolongs the LA effect when used as an adjuvant in the TAP block and improves the analgesic effects of the block.

Local anaesthetics and regional anaesthesia versus conventional analgesia for preventing persistent postoperative pain in adults and children

BACKGROUND

Regional anaesthesia may reduce the rate of persistent postoperative pain (PPP), a frequent and debilitating condition. This review was originally published in 2012 and updated in 2017.

OBJECTIVES

To compare local anaesthetics and regional anaesthesia versus conventional analgesia for the prevention of PPP beyond three months in adults and children undergoing elective surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, and Embase to December 2016 without any language restriction. We used a combination of free text search and controlled vocabulary search. We limited results to randomized controlled trials (RCTs). We updated this search in December 2017, but these results have not yet been incorporated in the review. We conducted a handsearch in reference lists of included studies, review articles and conference abstracts. We searched the PROSPERO systematic review registry for related systematic reviews.

SELECTION CRITERIA

We included RCTs comparing local or regional anaesthesia versus conventional analgesia with a pain outcome beyond three months after elective, non-orthopaedic surgery.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial quality and extracted data and adverse events. We contacted study authors for additional information. We presented outcomes as pooled odds ratios (OR) with 95% confidence intervals (95% CI), based on random-effects models (inverse variance method). We analysed studies separately by surgical intervention, but pooled outcomes reported at different follow-up intervals. We compared our results to Bayesian and classical (frequentist) models. We investigated heterogeneity. We assessed the quality of evidence with GRADE.

MAIN RESULTS

In this updated review, we identified 40 new RCTs and seven ongoing studies. In total, we included 63 RCTs in the review, but we were only able to synthesize data on regional anaesthesia for the prevention of PPP beyond three months after surgery from 41 studies, enrolling a total of 3143 participants in our inclusive analysis.Evidence synthesis of seven RCTs favoured epidural anaesthesia for thoracotomy, suggesting the odds of having PPP three to 18 months following an epidural for thoracotomy were 0.52 compared to not having an epidural (OR 0.52 (95% CI 0.32 to 0.84, 499 participants, moderate-quality evidence). Simlarly, evidence synthesis of 18 RCTs favoured regional anaesthesia for the prevention of persistent pain three to 12 months after breast cancer surgery with an OR of 0.43 (95% CI 0.28 to 0.68, 1297 participants, low-quality evidence). Pooling data at three to 8 months after surgery from four RCTs favoured regional anaesthesia after caesarean section with an OR of 0.46, (95% CI 0.28 to 0.78; 551 participants, moderate-quality evidence). Evidence synthesis of three RCTs investigating continuous infusion with local anaesthetic for the prevention of PPP three to 55 months after iliac crest bone graft harvesting (ICBG) was inconclusive (OR 0.20, 95% CI 0.04 to 1.09; 123 participants, low-quality evidence). However, evidence synthesis of two RCTs also favoured the infusion of intravenous local anaesthetics for the prevention of PPP three to six months after breast cancer surgery with an OR of 0.24 (95% CI 0.08 to 0.69, 97 participants, moderate-quality evidence).We did not synthesize evidence for the surgical subgroups of limb amputation, hernia repair, cardiac surgery and laparotomy. We could not pool evidence for adverse effects because the included studies did not examine them systematically, and reported them sparsely. Clinical heterogeneity, attrition and sparse outcome data hampered evidence synthesis. High risk of bias from missing data and lack of blinding across a number of included studies reduced our confidence in the findings. Thus results must be interpreted with caution.

AUTHORS' CONCLUSIONS

We conclude that there is moderate-quality evidence that regional anaesthesia may reduce the risk of developing PPP after three to 18 months after thoracotomy and three to 12 months after caesarean section. There is low-quality evidence that regional anaesthesia may reduce the risk of developing PPP three to 12 months after breast cancer surgery. There is moderate evidence that intravenous infusion of local anaesthetics may reduce the risk of developing PPP three to six months after breast cancer surgery.Our conclusions are considerably weakened by the small size and number of studies, by performance bias, null bias, attrition and missing data. Larger, high-quality studies, including children, are needed. We caution that except for breast surgery, our evidence synthesis is based on only a few small studies. On a cautionary note, we cannot extend our conclusions to other surgical interventions or regional anaesthesia techniques, for example we cannot conclude that paravertebral block reduces the risk of PPP after thoracotomy. There are seven ongoing studies and 12 studies awaiting classification that may change the conclusions of the current review once they are published and incorporated.

Postoperative Analgesia by a Transversus Abdominis Plane Block Using Different Concentrations of Ropivacaine for Abdominal Surgery: A Meta-Analysis

BACKGROUND

Transversus abdominis plane block (TAPB) has been proven to be an effective means of postoperative anesthesia, but the optimum effective concentration of ropivacaine warrants further research.

OBJECTIVE

This study aimed to identify the optimal ropivacaine concentration of TAPB using a meta-analysis.

MATERIALS AND METHODS

This study consisted of a meta-analysis of randomized controlled trials (RCTs). We searched online databases, including PubMed, Embase, the Cochrane Database of Systematic Reviews, and Web of Science. RCTs investigating the 24-hour postoperative opioid consumption and the rest and dynamic pain scores 2, 12, and 24 hours after surgery were included in this analysis. We also assessed opioid-related side-effects and patient satisfaction 24 hours after surgery.

RESULTS

Nineteen RCTs (1217 patients) were included in this meta-analysis, which showed that only TAPB with 0.375% and 0.5% ropivacaine was able to reduce opioid consumption 24 hours after surgery by weighted mean differences of -6.55 and -4.44 mg (morphine IV equivalents), respectively (P<0.05). A meta-regression analysis did not reveal an association between the local anesthetic dose (in mg), surgery, anesthesia, block timing, and the TAPB effect on opioid consumption. Ropivacaine concentrations of 0.375% and 0.5% reduced the 2-hour postoperative pain score and reduced the incidence of nausea and vomiting, but this analgesic effect disappeared at 12 and 24 hours. Only TAPB with 0.375% ropivacaine improved the degree of satisfaction 24 hours after surgery (weighted mean difference of 0.87 [0.08-1.66], P=0.03).

CONCLUSION

In terms of efficacy and safety, the use of 0.375% ropivacaine for TAPB is preferred in the clinical work.

Incidence and severity of chronic pain after caesarean section: A systematic review with meta-analysis

BACKGROUND

The frequency of caesarean section has increased dramatically in recent decades. Despite this, robust data regarding the consequences of caesarean section in terms of developing chronic postsurgical pain (CPSP) are still lacking.

OBJECTIVE

This systematic review analysed the incidence and severity of CPSP in women 3 to less than 6, 6 to less than 12, and at least 12 months after caesarean section.

DESIGN

Systematic review of prospective and retrospective observational studies and randomised controlled trials with meta-analysis.

DATA SOURCE

We searched MEDLINE to May 2015.

ELIGIBILITY CRITERIA

We included all studies investigating the incidence and/or severity of CPSP at least 3 months after caesarean section. The primary outcome was chronic postsurgical wound pain (CPSP 'wound'). Secondary outcomes were persistent pain in the back area, pelvic region or reported as residual pain, and severity of 'birth-related' chronic pain.

RESULTS

Meta-analysis using the random-effects model based on 15 studies (n = 4475) reporting CPSP 'wound' at 3 to less than 6 months after caesarean section revealed an incidence of 15.4% [95% confidence interval (CI): 9.9 to 20.9%]. For 6 to less than 12 and at least 12 months after caesarean section, the incidence of CPSP 'wound' was estimated at 11.5% (95% CI: 8.1 to 15.0%, n = 3345) and 11.2% (95% CI: 7.4 to 15.0%, n = 3451), respectively. Meta-regression analysis using the publication year as predictor revealed stable CPSP 'wound' incidences at each postoperative time slot from 2002 to the present. Of those patients who reported chronic pain, 9.6% (95% CI: 0.0 to 21.0%) had severe pain, 23.5% (95% CI: 10.0 to 37.0%) had moderate pain and 49.2% (95% CI: 18.9 to 79.4%) had mild pain at 6 months.

LIMITATIONS

Major limitations are high statistical heterogeneity of the meta-analyses and inconsistencies in reporting severity of chronic 'birth-related' pain.

CONCLUSION

This meta-analysis finds a clinically relevant incidence of CPSP 'wound' after caesarean section ranging from 15% at 3 months to 11% at 12 months or longer that has been largely stable in recent years.

The Analgesic Efficacy of Ultrasound-Guided Transversus Abdominis Plane Block in Adult Patients: A Meta-Analysis

BACKGROUND

Previous meta-analyses of the transversus abdominis plane (TAP) block have examined a maximum of 12 articles, including fewer than 650 participants, and have not examined the effect of ultrasound-guided techniques specifically. Recently, many trials that use ultrasound approaches to TAP block have been published, which report conflicting analgesic results. This meta-analysis aims to evaluate the analgesic efficacy of ultrasound-guided TAP blocks exclusively for all types of abdominal surgeries in adult patients.

METHODS

This meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. The primary outcome was cumulative IV morphine consumption at 6 hours postoperatively, analyzed according to the type of surgery, the type of surgical anesthesia, the timing of injection, the block approach adopted, and the presence of postoperative multimodal analgesia. Secondary outcomes included IV morphine consumption at 24 hours postoperatively; pain scores at rest and on movement at 6 and 24 hours postoperatively; and postoperative nausea and vomiting, pruritus, and rates of complications.

RESULTS

Thirty-one controlled trials including 1611 adult participants were identified. Independent of the type of surgery (abdominal laparotomy, abdominal laparoscopy, and cesarean delivery) but not independent of the type of surgical anesthesia (general anesthesia, spinal anesthesia with or without intrathecal long-acting opioid), ultrasound-guided TAP block reduced IV morphine consumption at 6 hours postoperatively by a mean difference of 6 mg (95% confidence interval [CI], -7 to -4 mg; I2 = 94%; P < 0.00001). The magnitude of the reduction in morphine consumption at 6 hours postoperatively was not influenced by the timing of injection (I2 = 0%; P = 0.72), the block approach adopted (I2 = 0%; P = 0.72), or the presence of postoperative multimodal analgesia (I2 = 73%; P = 0.05). This difference persisted at 24 hours postoperatively (mean difference, -11 mg; 95% CI, -14 to -8 mg; I2 = 99%; P < 0.00001). Pain scores at rest and on movement were reduced at 6 hours postoperatively (mean difference at rest, -10; 95% CI, -15 to -5; I2 = 92%; P = 0.0002; mean difference on movement, -9; 95% CI, -14 to -5; I2 = 58%; P < 0.00001). There were neither differences in the incidence of postoperative nausea and vomiting (I2 = 1%; P = 0.59) nor in the pruritus (I2 = 12%; P = 0.58) Two minor complications (1 bruise and 1 anaphylactoid reaction) were reported in 1028 patients.

CONCLUSIONS

Ultrasound-guided TAP block provides marginal postoperative analgesic efficacy after abdominal laparotomy or laparoscopy and cesarean delivery. However, it does not provide additional analgesic effect in patients who also received spinal anesthesia containing a long-acting opioid. The minimal analgesic efficacy is independent of the timing of injection, the approach adopted, or the presence of postoperative multimodal analgesia. Because of heterogeneity of the results, these findings should be interpreted with caution.

Endogenous opiates and behavior: 2014

This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants). This paper is the thirty-seventh consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2014 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior (endogenous opioids and receptors), and the roles of these opioid peptides and receptors in pain and analgesia (pain and analgesia); stress and social status (human studies); tolerance and dependence (opioid mediation of other analgesic responses); learning and memory (stress and social status); eating and drinking (stress-induced analgesia); alcohol and drugs of abuse (emotional responses in opioid-mediated behaviors); sexual activity and hormones, pregnancy, development and endocrinology (opioid involvement in stress response regulation); mental illness and mood (tolerance and dependence); seizures and neurologic disorders (learning and memory); electrical-related activity and neurophysiology (opiates and conditioned place preferences (CPP)); general activity and locomotion (eating and drinking); gastrointestinal, renal and hepatic functions (alcohol and drugs of abuse); cardiovascular responses (opiates and ethanol); respiration and thermoregulation (opiates and THC); and immunological responses (opiates and stimulants).

Transversus abdominis plane block does not improve early or late pain outcomes after Cesarean delivery: a randomized controlled trial

OBJECTIVES

Cesarean delivery is a common surgical procedure with anticipated substantial postoperative pain. The addition of a transversus abdominis plane block (TAPB) to a multimodal analgesic regimen that includes intrathecal morphine may provide improved early pain outcomes and decrease the risk of chronic post-surgical pain. The purpose of this research was to assess the ability of an ultrasound-guided TAPB with low-dose ropivacaine to decrease early postoperative pain, opioid consumption, and risk of developing persistent pain when compared with a placebo block.

METHODS

Eighty-three women were randomly assigned to either a treatment (0.25% ropivacaine) or control group (0.9% saline) in this double-blind trial, and 74 women were included in the final analysis. Ultrasound-guided TAPBs were performed with an injection of 20 mL of study solution per side. The primary outcome measures of this study were: pain at rest and pain after movement measured with a numeric rating scale, results of the Quality of Recovery-40 (QoR-40) questionnaire, and opioid consumption at 24 hr. These were used with an a priori sample size calculation to detect a 30% reduction in pain scores, a 10% improvement in QoR-40 score, and a 50% reduction in opioid consumption. Health quality and physical functioning were assessed using the Short Form 36 (SF-36®) Health Survey at 30 days and six months.

RESULTS

Assessment at 24 hr after Cesarean delivery revealed no clinically important differences between groups in postoperative pain, QoR-40, or opioid consumption. There were no clinically important differences between groups regarding measures of nausea, pruritus, vomiting, urine retention (2, 24, and 48 hr postoperatively), 24-hr QoR-40 sub-dimensions, or the SF-36 Health Survey (30 days and six months postoperatively).

CONCLUSIONS

Ultrasound-guided TAPB did not improve postoperative pain, quality of recovery, or opioid consumption 24 hr following surgery. Similar health and functioning (SF-36) at 30 days and six months were reported by both groups. This trial was registered at ClinicalTrials.gov number: NCT01261637.

Feasibility and analgesic efficacy of the transversus abdominis plane block after single-port laparoscopy in patients having bariatric surgery

Purpose

The transversus abdominis plane (TAP) block is a technique increasingly used for analgesia after surgery on the anterior abdominal wall. We undertook this study to determine the feasibility and analgesic efficacy of ultrasound-guided TAP blocks in morbidly obese patients. We describe the dermatomal spread of local anesthetic in TAP blocks administered, and test the hypothesis that TAP blocks decrease visual analog scale (VAS) scores.

Patients and methods

After ethics committee approval and informed consent, 35 patients with body mass index >35 undergoing single-port sleeve gastrectomy (SPSG) were enrolled. All patients received balanced general anesthesia, followed by intravenous patient-controlled analgesia (IV-PCA; hydromorphone) postoperatively; all reported VAS >3 upon arrival to the recovery room. From the cohort of 35 patients having single-port laparoscopy (SPL), a sealed envelope method was used to randomly select ten patients to the TAP group and 25 patients to the control group. The ten patients in the TAP group received ultrasound-guided TAP blocks with 30 mL of 0.2% Ropivacaine injected bilaterally. The dermatomal distribution of the sensory block (by pinprick test) was recorded. VAS scores for the first 24 hours after surgery and opioid use were compared between the IV-PCA+TAP block and IV-PCA only groups.

Results

Sensory block ranged from T5–L1. Mean VAS pain scores decreased from 8 ± 2 to 4 ± 3 (P=0.04) within 30 minutes of TAP block administration. Compared with patients given IV-PCA only, significantly fewer patients who received TAP block had moderate or severe pain (VAS 4–10) after block administration at 6 hours and 12 hours post-surgery. However, cumulative consumption of hydromorphone at 24 hours after SPSG surgery was similar for both groups.

Conclusion

Ultrasound-guided TAP blocks in morbidly obese patients are feasible and result in satisfactory analgesia following SPSG in the immediate postoperative period.