Effect of Lidocaine 2% Versus Bupivacaine 0.5% and 1 Versus 2 Dual Separate Injections on Onset and Duration of Ultrasound-Guided Wrist Blocks: A Blinded 2 × 2 Factorial Randomized Clinical Trial.

BACKGROUND: Local anesthetics are often selected or mixed to accomplish faster onset of anesthesia. However, with ultrasound guidance, local anesthetics are delivered with greater precision, which may shorten the onset time with all classes of local anesthetics. In this study, we compared onset time and duration of ultrasound-guided wrist blocks with a fast onset versus a longer lasting local anesthetic administered via single or dual (spatially separate) injections at the level of the midforearm. METHODS: In this randomized clinical trial, 36 subjects scheduled for carpal tunnel release were randomly assigned to receive ultrasound-guided median and ulnar nerve blocks with lidocaine 2% or bupivacaine 0.5% via single or dual injections (n = 9 in each group). Subjects fulfilled the study requirements. The main outcome variables were onset and duration of sensory blockade, which were tested separately in 2 (drug) × 2 (injection) analysis of variances (ANOVAs) with interaction terms. RESULTS: Sensory block onset time did not differ significantly between subjects given lidocaine 2% (9.2 ± 3.4 minutes) or bupivacaine 0.5% (9.5 ± 3.1 minutes) (P = .76; mean difference, -0.3 ± 1.1 minutes [95% confidence interval {CI}, -2.5 to 1.9]) or between the single- (9.6 ± 2.8 minutes) and dual- (9.1 ± 3.6 minutes) injection groups (P = .69; mean difference, -0.4 ± 1.1 minutes [95% CI, -1.8 to 2.6]). Sensory duration was longer for subjects in the bupivacaine 0.5% group (27.3 ± 11.6 hours) than for subjects in the lidocaine 2% group (8.4 ± 4.1 hours) (P < .001; 95% CI, 12.7-25.1). However, sensory duration in the single- (15.7 ± 12.5 hours) and dual- (19.4 ± 13.1 hours) injection groups did not differ significantly (P = .28; mean difference, -3.7 ± 4.3 hours [95% CI, -12.6 to 5.1]). CONCLUSIONS: No significant effect was found for onset time between lidocaine 2% and bupivacaine 0.5% used in ultrasound-guided wrist blocks. Dual injections did not shorten onset time. Since mean nerve block duration was longer with bupivacaine 0.5%, our results suggest that the selection of local anesthetic for the median and ulnar nerves at the level of the midforearm should be based on the desired duration of the block and not on its speed of onset.

Selective periarticular blocks for postoperative pain after hip and knee arthroplasty.

PURPOSE OF REVIEW: This review aims to provide an overview of selective periarticular blocks for postoperative pain after hip and knee arthroplasty and the current evidence for their use. RECENT FINDINGS: Most interventional analgesia techniques for hip and knee arthroplasty result in a motor block and muscle weakness. Therefore, these are not well suited for fast-track protocols. In contrast, selective pericapsular infiltration techniques provide selective joint sensory block without an associated motor block. This facilitates postoperative pain management and avoids impairing ambulation and early rehabilitation. SUMMARY: The pericapsular blocks of the hip (pericapsular nerve group block, iliopsoas plane block, hip block), genicular nerves block, and infiltration between the popliteal artery and the capsule of the knee play an increasingly important role in providing postoperative analgesia after hip and knee arthroplasty without impeding fast-track protocols.

Extended release bupivacaine formulations for postoperative analgesia: an update.

PURPOSE OF REVIEW: New formulations of local anesthetics with sustained release and longer duration of action are being developed to improve patient outcomes following surgery. This review summarizes the efficacy and safety of the three most recently developed extended-release formulations of the local anesthetic, bupivacaine. RECENT FINDINGS: Bupivacaine liposome injectable suspension (EXPAREL) encapsulates bupivacaine in biodegradable liposomes. It is currently the only extended-release formulation of bupivacaine approved by the FDA for infiltration of the tissues during surgery and for interscalene nerve block analgesia following shoulder surgery. SABER-Bupivacaine and HTX-011, are extended-release bupivacaine products in active development. Available data suggest relative safety and efficacy of all three formulations, although more data are needed to define their indications and dosing. SUMMARY: Extended-release bupivacaine formulations are promising alternatives to prolong duration of analgesia. To date, only EXPAREL has been approved by the FDA for tissue infiltration during surgery and for interscalene nerve block.

Pericapsular nerve group block: a 3D CT scan imaging study to determine the spread of injectate.

BACKGROUND: Current understanding of the mechanism of action of the pericapsular nerve group (PENG) block is primarily based on cadaver studies. We performed an imaging study in patients undergoing hip surgery to enhance the understanding of the analgesic mechanisms following a PENG block. MATERIALS AND METHODS: 10 patients scheduled for hip surgery received an ultrasound-guided PENG block with 18 mL of 0.5% ropivacaine mixed with 2 mL of a contrast agent. After completion of the block, a high-resolution CT scan was performed to obtain a three-dimensional reconstruction of the injectate's dispersion. RESULTS: The CT imaging revealed that injectate was mainly confined to the epimysium of the iliacus and the psoas muscle, with a minor spread to the hip capsule. Contrast dye was detected within the iliacus and/or the psoas muscle in all patients. No observed spread to either the subpectineal plane or the obturator foramen was detected. CONCLUSION: Our study suggests that the analgesic effect of the PENG block may be related to the block of the branches of the femoral nerve traveling within the iliopsoas muscle without a spread pattern commensurate with the block of the obturator nerve. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT06062134).

Motor-Sparing Nerve Blocks Can Improve the Results of Digit Tendon Surgery: A Case Report.

A 56-year-old woman presented with flexion dysfunction of the fifth digit 6 weeks after surgical repair of a flexor digitorum profundus laceration. She was scheduled for surgical adhesiolysis and restoration of the functionality of the finger. Intraoperative monitoring of the range of motion by active flexion was deemed important to prevent incomplete release of the tendon and residual dysfunction. Distal median and ulnar nerve blocks were used for anesthesia with the patient's ability to flex the finger. This case suggests that motor-sparing peripheral nerve blocks can improve functional outcome in certain hand surgeries.

Quadratus lumborum block: an imaging study of three approaches.

BACKGROUND AND OBJECTIVES: Different injection techniques for the quadratus lumborum (QL) block have been described. Data in human cadavers suggest that the transverse oblique paramedian (TOP) QL3 may reach the thoracic paravertebral space more consistently than the QL1 and QL2. However, the distribution of injectate in cadavers may differ from that in patients. Hence, we assessed the distribution of the injectate after the QL1, QL2, and TOP QL3 techniques in patients. MATERIALS AND METHODS: Thirty-four patients scheduled for abdominal surgery received QL blocks postoperatively; 26 patients received bilateral and 8 patients received unilateral blocks. Block injections were randomly allocated to QL1, QL2, or TOP QL3 techniques (20 blocks per each technique). The injections consisted of 18 mL of ropivacaine 0.375% with 2 mL of radiopaque contrast, injected lateral or posterior to the QL muscle for the QL1 and QL2 techniques, respectively. For the TOP QL3, the injection was into the plane between the QL and psoas muscles, proximal to the L2 transverse process. Two reviewers, blinded to the allocation, reviewed three-dimensional computed tomography (3D-CT) images to assess the distribution of injectate. RESULTS AND DISCUSSION: The QL1 block spread in the transversus abdominis plane (TAP), QL2 in the TAP, and posterior aspect of the QL muscle, whereas TOP QL3 spread consistently in the anterior aspect of the QL muscle with occasional spread to the lumbar and thoracic paravertebral areas. CONCLUSIONS: The spread of injectate after QL1, QL2, and QL3 blocks, resulted in different distribution patterns, primarily in the area of injection. The TOP QL3 did not result in consistent interfascial spread toward the thoracic paravertebral space.

Fascia iliaca compartment blocks: Different techniques and review of the literature.

The fascia iliaca compartment block has been promoted as a valuable regional anesthesia and analgesia technique for lower limb surgery. Numerous studies have been performed, but the evidence on the true benefits of the fascia iliaca compartment block is still limited. Recent anatomical, radiological, and clinical research has demonstrated the limitations of the landmark infrainguinal technique. Nevertheless, this technique is still valuable in situations where ultrasound cannot be used because of lack of equipment or training. With the introduction of ultrasound, a new suprainguinal approach of the fascia iliaca has been described. Research has demonstrated that this technique leads to a more reliable block of the target nerves than the infrainguinal techniques. However, more research is needed to determine the place of this technique in clinical practice.

Peripheral nerve catheters: A critical review of the efficacy.

Continuous peripheral nerve blocks are commonly used for postoperative analgesia after surgery. However, catheter failure may occur due to either primary (incorrect insertion) or secondary reasons (displacement, obstruction, disconnection). Catheter failure results in unanticipated pain, need for opioid use, and risk of readmission or delay in hospital discharge. This review aimed to assess definition and frequency of catheter failure, and discuss the alternatives to prolong duration of single-shot nerve blocks. A literature search was performed on peripheral catheters reporting failure as the main outcome measure. Thirty-three studies met the selection criteria, comprising 2711 catheters. Literature review suggests that peripheral nerve catheters have clinically significant failure rate when the assessment is performed using an objective (imaging) method. Subjective methods of assessment (without imaging) may underestimate the incidence of catheter failure.

In search of the Holy Grail: Poisons and extended release local anesthetics.

Regional anesthesia has been advocated as adjunct to a multimodal analgesia regimen. The limited duration of the action of available local anesthetics limits their application. Catheters, perineural or IV adjuvants, or repetition of blocks are modalities available to prolong the analgesic benefit of LRA. All of these approaches have their shortcomings. New extended release local anesthetic formulations may provide time-efficient and longer duration of analgesia with a single injection. Available data on liposomal bupivacaine are promising, and more recently, it has been FDA approved for use in interscalene brachial plexus block but not for other nerve blocks at this time. Several other new formulations and compounds, such as HTX-011, Neosaxitoxin, and SABER-Bupivacaine, are also being developed and tested for their safety and analgesic potential.