Transversus Abdominis Plane Block: A Narrative Review.

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.

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

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

A randomized comparison between interscalene and combined infraclavicular-suprascapular blocks for arthroscopic shoulder surgery.

BACKGROUND: This randomized trial aimed to evaluate combined infraclavicular-suprascapular blocks (ICB-SSBs) as a diaphragm-sparing alternative to interscalene blocks (ISBs) for arthroscopic shoulder surgery. We hypothesized that ICB-SSB would provide equivalent postoperative analgesia to ISB 30 min after surgery without the risk of hemidiaphragmatic paralysis. METHODS: Following research ethics board approval and written informed consent, participants in the ISB group received an ultrasound-guided ISB with 20 mL of levobupivacaine 0.25% and epinephrine 5 µg·mL-1. In the ICB-SSB group, ultrasound-guided ICB (20 mL) and SSB (10 mL) were carried out using the same local anesthetic. Thirty minutes after the block was performed, a blinded investigator assessed the presence of hemidiaphragmatic paralysis. Subsequently, all patients underwent general anesthesia. Postoperatively, a blinded investigator recorded pain scores at rest at 0.5, 1, 2, 3, 6, 12 and 24 hr. Consumption of intra- and postoperative narcotics was also tabulated. RESULTS: Compared to its ICB-SSB counterpart, the ISB group displayed non-equivalent (i.e., lower) postoperative pain scores at 30 min (difference of the medians, -4; 99% confidence interval [CI], -6 to -3), required less cumulative morphine iv at 24 hr (difference of the means, -6.1 mg; 95% CI, -10.5 to -1.6), and resulted in a higher incidence of hemidiaphragmatic paralysis (18/20 vs 0/20 patients, respectively; P < 0.001). Although postoperative pain scores at one, two, and three hours appeared lower in the ISB group, the upper bounds of the 99% CIs did not exceed the equivalence margin. CONCLUSION: Compared with ICB-SSB, ISB provided non-equivalent (i.e., lower) postoperative pain scores 30 min after arthroscopic shoulder surgery. Thereafter, postoperative analgesia was comparable between the two groups. Further trials are required to compare ISB with ICB-SSB using a proximal (i.e., costoclavicular) technique for ICB. TRIAL REGISTRATION: www.clinicaltrials.gov , NCT02993939. Registered 12 December 2016.

Treatment of complex regional pain syndrome: an updated systematic review and narrative synthesis.

PURPOSE: Although multiple treatments have been advocated for complex regional pain syndrome (CRPS), the levels of supportive evidence are variable and sometimes limited. The purpose of this updated review is to provide a critical analysis of the evidence pertaining to the treatment of CRPS derived from recent randomized-controlled trials (RCTs). SOURCE: The MEDLINE, EMBASE, Psychinfo, and CINAHL databases were searched to identify relevant RCTs conducted on human subjects and published in English between 1 May 2009 and 24 August 2017. PRINCIPAL FINDINGS: The search yielded 35 RCTs of variable quality pertaining to the treatment of CRPS. Published trials continue to support the use of bisphosphonates and short courses of oral steroids in the setting of CRPS. Although emerging evidence suggests a therapeutic role for ketamine, memantine, intravenous immunoglobulin, epidural clonidine, intrathecal clonidine/baclofen/adenosine, aerobic exercise, mirror therapy, virtual body swapping, and dorsal root ganglion stimulation, further confirmatory RCTs are warranted. Similarly, trials also suggest an expanding role for peripheral sympathetic blockade (i.e., lumbar/thoracic sympathetic, stellate ganglion, and brachial plexus blocks). CONCLUSIONS: Since our prior systematic review article (published in 2010), 35 RCTs related to CRPS have been reported. Nevertheless, the quality of trials remains variable. Therefore, further research is required to continue investigating possible treatments for CRPS.

Ultrasound with neurostimulation compared with ultrasound guidance alone for lumbar plexus block: A randomised single blinded equivalence trial.

BACKGROUND: Ultrasound-guided lumbar plexus blocks usually require confirmatory neurostimulation. A simpler alternative is to inject local anaesthetic inside the posteromedial quadrant of the psoas muscle under ultrasound guidance. OBJECTIVE: We hypothesised that both techniques would result in similar total anaesthesia time, defined as the sum of performance and onset time. DESIGN: A randomised, observer-blinded, equivalence trial. SETTING: Ramathibodi Hospital and Maharaj Nakorn Chiang Mai Hospital (Thailand) from 12 May 2016 to 10 January 2017. PATIENTS: A total of 110 patients undergoing total hip or knee arthroplasty, who required lumbar plexus block for postoperative analgesia. INTERVENTION: In the combined ultrasonography-neurostimulation group, quadriceps-evoked motor response was sought at a current between 0.2 and 0.8 mA prior to local anaesthetic injection (30 ml of lidocaine 1% and levobupivacaine 0.25% with epinephrine 5 µg ml and 5 mg of dexamethasone). In the ultrasound guidance alone group, local anaesthetic was simply injected inside the posteromedial quadrant of the psoas muscle. MAIN OUTCOMES MEASURES: We measured the total anaesthesia time, the success rate (at 30 min), the number of needle passes, block-related pain, cumulative opioid consumption (at 24 h) and adverse events (vascular puncture, paraesthesia, local anaesthetic spread to the epidural space). The equivalence margin was 7.4 min. RESULTS: Compared with ultrasound guidance alone, combined ultrasonography-neurostimulation resulted in decreased mean (±SD) total anaesthesia time [15.3 (±6.5) vs. 20.1 (±9.0) min; mean difference, -4.8; 95% confidence interval, -8.1 to -1.9; P = 0.005] and mean (±SD) onset time [10.2 (±5.6) vs. 15.5 (±9.0) min; P = 0.004). No inter-group differences were observed in terms of success rate, performance time, number of needle passes, block-related pain, opioid consumption or adverse events. CONCLUSION: Although the ultrasonography-neurostimulation technique results in a shorter total anaesthesia time compared with ultrasound guidance alone, this difference falls within our accepted equivalence margin (±7.4 min). TRIAL REGISTRATION: www.clinicaltrials in the (Study ID: TCTR20160427003).

A randomized comparison between costoclavicular and paracoracoid ultrasound-guided infraclavicular block for upper limb surgery.

BACKGROUND: This two-centre randomized trial compared costoclavicular and paracoracoid ultrasound-guided infraclavicular brachial plexus block in patients undergoing upper limb surgery. We hypothesized that both techniques would result in similar onset times and designed the study as an equivalence trial. METHODS: Ninety patients undergoing upper limb surgery at or distal to the elbow were randomly allocated to receive a costoclavicular (n = 45) or paracoracoid (n = 45) ultrasound-guided infraclavicular brachial plexus block. Both groups received a 35-mL mixture of 1% lidocaine-0.25% bupivacaine with epinephrine 5 µg·mL-1. In the costoclavicular group, local anesthetic was injected into the costoclavicular space in the middle of the three cords of the brachial plexus. In the paracoracoid group, local anesthetic was deposited dorsal to the axillary artery in the lateral infraclavicular fossa. A blinded observer recorded the block onset time (primary endpoint), success rate (i.e., surgical anesthesia), block-related pain scores, as well as the incidence of hemidiaphragmatic paralysis. Performance time and the number of needle passes were also recorded during the performance of the block. The total anesthesia-related time was defined as the sum of the performance and onset times. RESULTS: The mean (SD) onset times were comparable between the costoclavicular and paracoracoid groups [16.0 (7.5) min vs 16.8 (6.2) min, respectively; mean difference, 0.8; 95% confidence interval, -2.3 to 3.8; P = 0.61]. Furthermore, no intergroup differences were found in terms of performance time (P = 0.09), total anesthesia-related time (P = 0.90), surgical anesthesia (P > 0.99), and hemidiaphragmatic paralysis (P > 0.99). The paracoracoid technique required marginally fewer median [interquartile range] needle passes than the costoclavicular technique (2 [1-4] vs 2 [1-6], respectively; P = 0.048); however, procedural pain was comparable between the two study groups. CONCLUSION: Costoclavicular and paracoracoid ultrasound-guided infraclavicular blocks resulted in similar onset times. Furthermore, no intergroup differences were found in terms of performance times and success rates. Future dose-finding trials are required to elucidate the minimum effective volume of local anesthetic for costoclavicular infraclavicular blocks. This trial was registered at www.clinicaltrials.in.th (Study ID: TCTR20160525001).

A randomized comparison between intravenous and perineural dexamethasone for ultrasound-guided axillary block.

BACKGROUND: This randomized double-blinded trial compared the effect of intravenous and perineural dexamethasone (8 mg) on the duration of motor block for ultrasound (US)-guided axillary brachial plexus block (AXB). METHODS: Patients undergoing upper limb surgery with US-guided AXB were randomly allocated to receive preservative-free dexamethasone (8 mg) via intravenous (n = 75) or perineural (n = 75) administration. The local anesthetic agent, 1% lidocaine -0.25% bupivacaine (30 mL) with epinephrine 5 µg·mL-1, was identical in all subjects. Operators and patients were blinded to the nature of the intravenous and perineural injectate. A blinded observer assessed the block success rate (i.e., a minimal sensorimotor composite score of 14 out of 16 points at 30 min), block onset time, as well as the presence of surgical anesthesia. Postoperatively, the blinded observer contacted all patients with successful blocks to record the duration of motor block (primary outcome), sensory block, and postoperative analgesia. RESULTS: No intergroup differences were observed in terms of success rate, surgical anesthesia, and block onset time. Compared to intravenous administration, perineural dexamethasone provided longer mean (SD) durations for motor block [17.5 (4.6) hr vs 12.8 (4.5) hr; mean difference, 4.6 hr; 95% confidence interval [CI], -6.21 to -3.08; P < 0.001], sensory block [17.7 (5.1) hr vs 13.7 (5.0) hr; mean difference, 4.0 hr; 95% CI, -5.77 to -2.27; P < 0.001], and postoperative analgesia [21.1 (4.6) hr vs 17.1 (4.6) hr; mean difference, 4.0 hr; 95% CI, -5.70 to -2.30; P < 0.001]. CONCLUSION: Compared to intravenous dosing, perineural dexamethasone (8 mg) results in longer durations of sensorimotor block and postoperative analgesia for ultrasound-guided axillary block. This trial was registered at www.clinicaltrials.gov number, NCT02629835.

A randomized trial comparing axillary block versus targeted intracluster injection supraclavicular block for upper limb surgery.

PURPOSE: This randomized trial aimed to validate a new method for brachial plexus blockade, i.e., targeted intracluster injection supraclavicular block (TII SCB), by comparing it with ultrasound-guided axillary block (AXB). We hypothesized that TII SCB would result in a shorter total anesthesia-related time. METHODS: Forty patients undergoing upper limb surgery were randomized to ultrasound-guided TII SCB (n = 20) or AXB (n = 20). In the TII SCB group, we deposited 16 mL of lidocaine 1.5% with epinephrine 5 µg·mL(-1) into the largest neural cluster (i.e., brachial plexus trunks/divisions). Subsequently, an additional 16 mL was divided into equal aliquots and injected inside each satellite cluster. In the AXB group, 5.5 mL were deposited around the musculocutaneous nerve and 23.5 mL were injected at the 6 o'clock position of the axillary artery. The main outcome for comparison between the two groups was the total anesthesia-related time (defined as the sum of block performance and onset times). We also recorded the number of needle passes, procedural pain, and complications (vascular puncture, paresthesia). RESULTS: The TII SCB method provided a quicker mean (SD) onset time compared with the AXB group [9.5 (5.8) min vs 18.9 (6.1) min; mean difference, -9.5 min; 99% CI, -14.7 to -4.2; P < 0.001] and a shorter mean (SD) total anesthesia-related time [20.1 (5.0) min vs 27.2 (6.5) min; mean difference, -7.0 min; 95% CI, -10.9 to -3.1; P = 0.001]. There were no intergroup differences in terms of success rate (95%), procedural pain, vascular puncture and paresthesia. The AXB group displayed a faster performance time [8.2 (1.6) min vs 10.6 (2.6) min; P = 0.001] with fewer median [interquartile range] needle passes (3 [2-6] vs 5 [4-8]; P < 0.001). CONCLUSION: Ultrasound-guided TII SCB provides a quicker onset and a shorter total anesthesia-related time than ultrasound-guided AXB.

A randomized comparison between double-injection and targeted intracluster-injection ultrasound-guided supraclavicular brachial plexus block.

BACKGROUND: In this prospective, randomized, observer-blinded study, we compared double-injection (DI) ultrasound-guided supraclavicular block to a novel targeted intracluster-injection (TII) technique, whereby local anesthetic is injected inside the main and satellite neural clusters (confluences of trunks and divisions of the brachial plexus). METHODS: Ninety patients were randomly allocated to receive a DI (n = 45) or TII (n = 45) technique for ultrasound-guided supraclavicular block. The local anesthetic drug (lidocaine 1.5% with epinephrine 5 µg/mL) and total volume (32 mL) were identical in all subjects. In both groups, half the volume (16 mL) was injected inside the main neural cluster. For the DI technique, the second half (16 mL) was deposited at the "corner pocket" (intersection of the first rib and subclavian artery). In contrast, for the TII technique, the remaining half was divided into equal aliquots and injected inside every single satellite cluster. The main outcome variable was the total anesthesia-related time (sum of performance and onset times). RESULTS: Due to a quicker onset (mean ± standard deviation (SD): 10.1 ± 6.4 vs 18.5 ± 8.3 minutes; P < 0.0001), the total anesthesia-related time was shorter with the TII technique (21.2 ± 7.7 vs 27.7 ± 9.0 minutes; P = 0.001; 95% confidence interval for the difference of the means: 2.90-10.08 minutes). There were 0 (of 45) and 3 (of 45) surgical failures for the TII and DI group, respectively. Thus, the 2 methods achieved comparable rates of surgical anesthesia (93.3%-100.0%; 95% confidence interval for the difference of the success rates: -2.3% to 17.9%). No intergroup differences were observed in block-related pain scores and adverse events. The DI group required fewer needle passes (median ± interquartile range: 4 ± 2 vs 7 ± 3; P < 0.0001) as well as shorter needling (8.4 ± 2.9 vs 10.7 ± 2.7 minutes; P < 0.0001) and performance (9.0 ± 3.2 vs 11.2 ± 3.0 minutes; P = 0.001) times. CONCLUSION: Although DI and TII ultrasound-guided supraclavicular blocks seem to provide comparable success rates, we cannot exclude the possibility that an intergroup difference of 17.9% might have gone undetected. Due to its quick onset, the TII technique results in a shorter total anesthesia-related time.

Primary failure of thoracic epidural analgesia: revisited.

Primary failure of thoracic epidural analgesia (TEA) remains an important clinical problem, whose incidence can exceed 20% in teaching centers. Since loss-of-resistance (LOR) constitutes the most popular method to identify the thoracic epidural space, the etiology of primary TEA failure can often be attributed to LOR's low specificity. Interspinous ligamentous cysts, non-fused ligamenta flava, paravertebral muscles, intermuscular planes, and thoracic paravertebral spaces can all result in non-epidural LORs. Fluoroscopy, epidural waveform analysis, electrical stimulation, and ultrasonography have been proposed as confirmatory modalities for LOR.The current evidence derived from randomized trials suggests that fluoroscopy, epidural waveform analysis, and possibly electrical stimulation, could decrease the primary TEA failure to 2%. In contrast, preprocedural ultrasound scanning provides no incremental benefit when compared with conventional LOR. In the hands of experienced operators, real-time ultrasound guidance of the epidural needle has been demonstrated to provide comparable efficacy and efficiency to fluoroscopy.Further research is required to determine the most cost-effective confirmatory modality as well as the best adjuncts for novice operators and for patients with challenging anatomy. Moreover, future trials should elucidate if fluoroscopy and electrical stimulation could potentially decrease the secondary failure rate of TEA, and if a combination of confirmatory modalities could outperform individual ones.

A randomized comparison between bifurcation and prebifurcation subparaneural popliteal sciatic nerve blocks.

BACKGROUND: In this prospective, randomized, observer-blinded trial, we compared ultrasound-guided subparaneural popliteal sciatic nerve blocks performed either at or proximal to the neural bifurcation (B). We hypothesized that the total anesthesia-related time (sum of performance and onset times) would be decreased with the prebifurcation (PB) technique. METHODS: Ultrasound-guided posterior popliteal sciatic nerve block was performed in 68 patients. All subjects received an identical volume (30 mL) and mix of local anesthetic agent (1% lidocaine-0.25% bupivacaine-5 µg/mL epinephrine). In the PB group, the local anesthetic solution was deposited at the level of the common sciatic trunk, just distal to the intersection between its circular and elliptical sonographic appearances, inside the paraneural sheath. In the B group, the injection was performed inside the sheath between the tibial and peroneal divisions. A blinded observer recorded the success rate (complete tibial and peroneal sensory block at 30 minutes) and onset time. The performance time, number of needle passes, and adverse events (paresthesia, neural edema) were also recorded. All subjects were contacted 7 days after the surgery to inquire about the presence of persistent numbness or motor deficit. RESULTS: Both techniques resulted in comparable success rates (85%-88%; 95% confidence interval [CI] of the intergroup difference, -14% to 19%) and required similar performance times (8.1 minutes; 95% CI of the difference, -1.65 to 1.71 minutes), onset times (15.0-17.7 minutes; 95% CI of the difference, -7.65 to 2.31 minutes), and total anesthesia-related times (23.4-26.0 minutes; 95% CI of the difference, -7.83 to 2.74 minutes). The number of needle passes and incidence of paresthesia (25%-34%) were also similar between the 2 groups. Sonographic neural swelling was detected in 2 and 3 subjects in the PB and B groups, respectively. In all 5 cases, the needle was carefully withdrawn and the injection completed uneventfully. Patient follow-up 1 week after the surgery revealed 2 patients with residual numbness. In both instances, the latter had resolved by 1 month. CONCLUSION: When local anesthetic is injected inside the paraneural sheath, B and PB posterior popliteal sciatic nerve blocks result in comparable success and total anesthesia-related times. However, in light of the 95% CIs, we cannot exclude the possibility that an intergroup difference of 19% and 7.83 minutes might have gone undetected for success rate and total time, respectively.

Patient-Reported Quality of Recovery after Local Anesthesia versus Brachial Plexus Block in Hand Surgery: A Randomized Controlled Study.

BACKGROUND: Both local anesthesia (LA) and brachial plexus (BP) anesthesia are commonly used in hand surgery. LA has increased efficiency and reduced costs, but BP is often favored for more complex hand surgery, despite requiring greater time and resources. The primary objective of this study was to assess the quality of recovery of patients who received LA or BP block for hand surgery. Secondary objectives were to compare postoperative pain and opioid use. METHODS: This randomized, controlled, noninferiority study enrolled patients undergoing surgery distal to the carpal bones. Patients were randomized to either LA (wrist or digital block) or BP block (infraclavicular block) before surgery. Patients completed the Quality of Recovery-15 questionnaire on postoperative day (POD) 1. Pain level was assessed with a numeric pain rating scale, and narcotic consumption was recorded on POD1 and POD3. RESULTS: A total of 76 patients completed the study (LA, n = 46, BP, n = 30). No statistically significant difference was found for median Quality of Recovery-15 score between LA [127.5 (interquartile range, 28)] and BP block [123.5 (interquartile range, 31)]. The inferiority margin of LA to BP block at the 95% confidence interval was less than the minimal clinically important difference of 8, demonstrating noninferiority of LA compared with BP block. There was no statistically significant difference between LA and BP block for numeric pain rating scale scores or narcotic consumption on POD1 and POD3 ( P > 0.05). CONCLUSION: LA is noninferior to BP block for hand surgery with regard to patient-reported quality of recovery, postoperative pain, and narcotic use. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, II.

Cadaveric study investigating the femoral nerve-sparing volume for pericapsular nerve group (PENG) block.

BACKGROUND: This cadaveric study investigated the maximum effective volume of dye in 90% of cases (MEV90) required to stain the iliac bone between the anterior inferior iliac spine (AIIS) and the iliopubic eminence (IPE) while sparing the femoral nerve during the performance of pericapsular nerve group (PENG) block. METHODS: In cadaveric hemipelvis specimens, the ultrasound transducer was placed in a transverse orientation, medial and caudal to the anterior superior iliac spine in order to identify the AIIS, the IPE and the psoas tendon. Using an in-plane technique and a lateral-to-medial direction, the block needle was advanced until its tip contacted the iliac bone. The dye (0.1% methylene blue) was injected between the periosteum and psoas tendon. Successful femoral-sparing PENG block was defined as the non-staining of the femoral nerve on dissection. Volume assignment was carried out using a biased coin design, whereby the volume of dye administered to each cadaveric specimen depended on the response of the previous one. In case of failure (ie, stained femoral nerve), the next one received a lower volume (defined as the previous volume with a decrement of 2 mL). If the previous cadaveric specimen had a successful block (ie, non-stained femoral nerve), the next one was randomized to a higher volume (defined as the previous volume with an increment of 2 mL), with a probability of b=1/9, or the same volume, with a probability of 1-b=8/9. RESULTS: A total of 32 cadavers (54 cadaveric hemipelvis specimens) were included in the study. Using isotonic regression and bootstrap CI, the MEV90 for femoral-sparing PENG block was estimated to be 13.2 mL (95% CI: 12.0 to 20.0). The probability of a successful response was estimated to be 0.93 (95% CI: 0.81 to 1.00). CONCLUSION: For PENG block, the MEV90 of methylene blue required to spare the femoral nerve in a cadaveric model is 13.2 mL. Further studies are required to correlate this finding with the MEV90 of local anesthetic in live subjects.