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Objectives: In 2009 and again in 2012, the American Society of Regional Anesthesia and Pain Medicine assembled an expert panel to assess the evidence basis for ultrasound guidance as a nerve localization tool for regional anesthesia., Methods: The 2012 panel reviewed evidence from the first advisory but focused primarily on new information that had emerged since 2009. A new section was added regarding the accuracy and reliability of ultrasound for determining needle-to-nerve proximity. Jadad scores are used to rank study quality. Grades of recommendations consistent with their level of evidence are provided., Results: The panel offers recommendations based on synthesis and analysis of literature related to (1) the technical capabilities of ultrasound equipment and its operators, (2) comparison of ultrasound to other methods of nerve localization with regard to block characteristics, (3) comparison of block techniques where ultrasound is the sole nerve localization modality, and (4) major complications. Assessment of evidence strength and recommendations are made for upper- and lower-extremity, truncal, neuraxial, and pediatric blocks., Conclusions: Scientific evidence from the past 5 years has clarified and strengthened our understanding of ultrasound-guided regional anesthesia as a nerve localization tool. High-level evidence supports ultrasound guidance contributing to superior characteristics with selected blocks, although absolute differences with the comparator technique are often relatively small (especially for upper-extremity blocks). The clinical meaningfulness of these differences is likely of variable importance to individual practitioners. The use of ultrasound significantly reduces the risk of local anesthetic systemic toxicity as well as the incidence and intensity of hemidiaphragmatic paresis, but has no significant effect on the incidence of postoperative neurologic symptoms. WHAT'S NEW IN THIS UPDATE?: This evidence-based assessment of ultrasound-guided regional anesthesia reviews findings from our 2010 publication and focuses on new meta-analyses, randomized controlled trials, and large case series published since 2009. New to this exercise is an in-depth analysis of the accuracy and reliability of ultrasound guidance for identifying needle-to-nerve relationships. This version no longer addresses ultrasound for interventional pain medicine procedures, because the growth of that field demands separate consideration. Since our 2010 publication, new information has either supported or strengthened our original conclusions. There is no evidence that ultrasound is inferior to alternative nerve localization methods.

This scoping review examines the literature to determine whether the position of the needle tip relative to the target nerve is accurately and reliably detected during ultrasound (US)-guided regional anesthesia. The requisites for successful and safe needle tip positioning relative to the target nerve include accurate and reliable needle presentation by the machine, needle interpretation by the operator, nerve presentation by the machine, and nerve interpretation by the operator. Failure to visualize the needle tip is a common occurrence, frequently prompting operators to use needle and probe maneuvers, which are not necessarily based on evidence. Needle tip interpretation often relies on surrogate indicators that have not been validated. The acoustic resolution of modern portable US machines limits the extent to which nerve microanatomy can be reliably presented. Finally, our interpretation of the sonographic end points for local anesthetic injection that best balance success and safety for US-guided regional anesthesia continues to evolve., What's New: In order to determine whether or not the position of the needle tip relative to the target nerve is accurately and reliably detected during US-guided regional anesthesia, the available literature is reviewed and interpreted to address the following 4 questions.

The use of ultrasound guidance has revolutionized regional anesthesia practice. Ultrasound equipment disinfection techniques vary between institutions. To date, there are no large data set publications or evidence-based guidelines that describe risk-reduction techniques for infectious complications related to the use of ultrasound guidance for peripheral nerve blockade. We retrospectively reviewed the medical charts of 7476 patients who received ultrasound-guided single-injection peripheral nerve blockade from October 2003 to August 2013 using our institution's low-level disinfection technique in combination with a sterile transparent film barrier dressing to cover the ultrasound transducer. No indications of block-related infection were found. We conclude that using a practical and efficient low-level disinfection technique and sterile barrier dressing results in an extremely low rate of block-related infection following ultrasound-guided single-injection peripheral nerve blockade.

The use of thoracic paravertebral blocks (PVBs) for breast cancer surgery confers important analgesic benefits. Several ultrasound (US)-guided PVB approaches have been described, but still elusive is the ideal technique that (1) permits continuous visualization of the entire needle shaft and tip, (2) avoids aiming the needle tip and injectate directly toward the neuraxis, and (3) is easy to perform. Although the parasagittal view in-plane PVB approach satisfies the former 2 criteria, maneuvering the needle to reach the targeted paravertebral space can be difficult as its trajectory is often obstructed by the bony transverse processes. This brief technical report describes the "off-side" technique--a simple solution to the technical challenge posed by the double-fulcrum effect exerted first by the transducer and then by the adjacent inferior transverse process. Our "off-side" technique marks a departure from conventional US-guided regional anesthesia teaching that recommends positioning the target in the middle of the US field and may be useful in similar types of US-guided regional anesthesia procedures such as neuraxial blockade.

Background and Objectives: Despite ultrasound (US) guidance, sciatic nerve block (SNB) remains among the least performed peripheral blocks. By targeting the tissue plane between the gluteus maximus and quadratus femoris muscles, the US-guided subgluteal space technique may facilitate the performance of US-guided SNB. We aimed to evaluate whether the subgluteal space technique shortens SNB performance time in overweight and obese patients compared with the conventional infragluteal technique., Methods: Overweight and obese patients (body mass index, > 25 kg m ) undergoing US-guided SNB for knee arthroplasty received 30 mL admixture (1:2 lidocaine 2%; bupivacaine 0.5% with 1:200,000 epinephrine) in the tissue plane between the gluteus maximus and quadratus femoris (subgluteal space group) or around the sciatic nerve at the infragluteal level (infragluteal group). All patients received spinal anesthesia, continuous femoral nerve block, and postoperative multimodal analgesia. The primary outcome was SNB performance time defined as the time interval between placement of the US transducer on skin, and needle withdrawal after injection. Number of needle passes, procedural pain, SNB-related complications, SNB success, postoperative pain, and opioid consumption were also assessed., Results: Twenty-seven patients were assessed (subgluteal space, 14; infragluteal, 13). Mean SNB performance time was 4.4 minutes (95% confidence interval, 3.7-5.0) for the subgluteal space group and 9.0 minutes (95% confidence interval, 7.7-10.3) for the infragluteal group (P < 0.0001). Number of needle passes and procedural pain scores were lower in the subgluteal space group. There were no differences in SNB success or analgesic outcomes., Conclusions: The subgluteal space technique may be performed 50% faster, with no detectable differences in block success and analgesic efficacy, compared with the infragluteal technique for US-guided SNB in overweight and obese patients receiving multimodal analgesia. Injection of local anesthetics along tissue planes may produce similar block characteristics to perineural injection for US-guided SNB.

Background: Despite the laparoscopic approach, patients can suffer moderate to severe pain following bariatric surgery. This randomized controlled double-blinded trial investigated the analgesic efficacy of ultrasound-guided transversus abdominis plane (TAP) blocks for laparoscopic gastric-bypass surgery., Methods: Seventy patients undergoing laparoscopic gastric-bypass surgery were randomized to receive either bilateral ultrasound-guided subcostal TAP block injections after induction of general anesthesia or none. All patients received trocar insertion site local anesthetic infiltration and systemic analgesia. The primary outcome was cumulative opioid consumption (IV morphine equivalent) during the first 24 h postoperatively. Interval opioid consumption, pain severity scores, rates of nausea or vomiting, and rates of pruritus were measured during phase I recovery, and at 24 and 48 h postoperatively., Results: There was no difference in cumulative opioid consumption during the first 24 h postoperatively between the TAP (32.2 mg [95% CI, 27.6-36.7]) and control (35.6 mg [95% CI, 28.6-42.5]; P = 0.41) groups. Postoperative opioid consumptions during phase I recovery and the 24-48-h interval were similar between groups, as were pain scores at rest and with movement during all measured intervals. The rates of nausea or vomiting and pruritus were equivalent., Conclusions: Bilateral TAP blocks do not provide additional analgesic benefit when added to trocar insertion site local anesthetic infiltration and systemic analgesia for laparoscopic gastric-bypass surgery.

Background: Modern ultrasound (US) is an attractive alternative to anatomical landmark-, nerve stimulation-, and fluoroscopic-guided techniques for interventional procedures performed to treat chronic pain syndromes., Methods: In this review, we evaluated the effects of US guidance compared with traditional guidance techniques on performance, efficacy, and safety outcomes for interventional chronic pain procedures. We identified 46 studies, including 41 case series and 5 randomized trials of intermediate-to-good quality that investigated the use of US guidance for a diverse variety of chronic pain procedures., Results: Our results suggest that US guidance can match or improve performance- and safety-related outcomes compared with many anatomic landmark-, nerve stimulation-, and fluoroscopic-guided techniques for treating chronic pain., Conclusions: There are presently insufficient data to support improved efficacy with procedures performed with US guidance for relieving both short- and long-term chronic pain.

Background: Ultrasound (US) guidance for peripheral nerve blockade has gained popularity worldwide. The reported benefits of real-time sonographic visualization compared with traditional nerve localization techniques generally apply to procedural and technical block-related outcomes whereas acute pain-related outcomes are featured less prominently. In this review, we evaluated the effect of US guidance compared with traditional nerve localization techniques for interventional management of acute pain and acute pain-related outcomes., Methods: We performed a systematic search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Clinical Trials (from January 1990 to January 2011) to identify randomized controlled trials evaluating the effects of US guidance on acute pain and related outcomes compared with traditional nerve localization techniques. Studies were excluded if they did not report at least one of the following acute pain outcomes: pain severity, opioid consumption, sensory block duration, and time to first analgesic request. Related outcomes were classified as follows: patient related (opioid-related adverse effects, patient satisfaction, postoperative cognitive deficit); anesthesia related (unwanted motor block, perineural catheter failure, morbidity, development of chronic pain); surgery related (hospital readmission, ability to ambulate); and hospital related (length of stay, cost). Promising novel applications of US guidance for acute pain management were also sought for discussion purposes., Results: We identified 23 randomized controlled trials, including 1674 patients, that compared US guidance with and without peripheral nerve stimulation with peripheral nerve stimulation alone or anatomical landmark techniques. Of the 16 studies that evaluated pain severity, 8 reported improvement with US guidance; however, only 1 study reported a difference between US guidance and the comparator of >1 interval on the numeric rating pain scale. Eight studies evaluated sensory block duration and 3 of these reported prolonged block duration with US guidance. Seven studies evaluated opioid consumption, of which 3 reported a reduction with US guidance. Three studies evaluated time to first analgesic request, of which 2 favored US guidance. We uncovered no significant differences between US guidance and traditional nerve localization techniques for any other related outcome. US guidance was not found to be inferior compared with traditional nerve localization techniques for any outcome. Nonrandomized data suggest that US-guided transversus abdominis plane blocks may offer analgesic benefit over standard analgesic therapy, but has not been compared with an anatomical landmark technique., Conclusions: At present, there is insufficient evidence in the contemporary literature to define the effect of US guidance on acute pain and related outcomes compared with traditional nerve localization techniques for interventional acute pain management.

Background: When performing a supraclavicular brachial plexus block (SCB) under ultrasound (US) guidance, the needle may approach the nerves in-plane with the US beam from 1 of 2 directions relative to the transducer, lateral-to-medial (lateral) or medial-to-lateral (medial). We aimed to compare the rates of sensory and motor block of the 4 major peripheral nerves of the upper extremity following a lateral or medial needle approach for US-guided SCB., Methods: Eighty adult patients undergoing US-guided SCB for elective hand, wrist, forearm, or elbow procedures were randomized to either a lateral or medial needle approach. A 30-mL local anesthetic admixture (1:1 lidocaine 2%-bupivacaine 0.5% with 1:200,000 epinephrine) was injected to all patients. Sensory and motor function was assessed by a blinded observer at predetermined intervals. The primary outcome was the rate of sensory block in the distribution of the ulnar nerve measured 20 mins after block performance., Results: Seventy-two patients were included in the final analysis. Patient characteristics were similar between groups. The rate of ulnar nerve sensory block at 20 mins was 63% in the lateral group and 62% in the medial group (P = 0.81). The rate of ulnar nerve sensory block at 30 mins increased to 89% in the lateral and 84% in the medial group (P = 0.96). The rates of both sensory and motor block in the distributions of the median, radial, and musculocutaneous nerves were high and did not differ between groups at any measured time interval. The block performance time and the postoperative pain scores were similar between the 2 groups. Complications were minor and transient and did not differ between groups., Conclusions: The rates of sensory and motor block of all 4 major peripheral nerves of the upper extremity did not differ at any time following a lateral compared with medial needle approach for US-guided SCB. Regardless of needle approach, the rate of ulnar nerve sensory block was less compared with the other peripheral nerves following US-guided SCB.

Background: Ultrasound (US) guidance, in some instances, can increase the success rate and reduce the onset and procedure times for peripheral nerve blockade compared with traditional nerve localization techniques. The presumptive mechanism for these benefits is the ability to accurately inject local anesthetic circumferentially around the target nerve. We aimed to determine whether ensuring circumferential spread of local anesthetic is advantageous for US-guided popliteal sciatic nerve block., Methods: Sixty-four adult patients undergoing US-guided popliteal sciatic block for elective foot and ankle surgery were randomly assigned to 1 of 2 groups, circumferential or single-location injection. Using a short-axis nerve view and out-of-plane needle approach, the needle tip was advanced to the posterior external surface of the sciatic nerve. A 30-mL local anesthetic admixture (1:1 lidocaine 2%/bupivacaine 0.5% with 1:200,000 epinephrine) was injected either entirely at this location (single location) or incrementally at multiple locations to ensure circumferential spread around the sciatic nerve (circumferential). Sensory and motor functions were assessed by a blinded observer at predetermined intervals. The primary outcome was sensory block defined as loss of sensation to pinprick in the distribution of both tibial and common peroneal nerves at 30 mins after injection., Results: Sensory block was achieved in 94% of patients in the circumferential injection group compared with 69% in the single-location injection group (P = 0.010). There were no differences detected in block performance time, pain during block performance, or block-related complications between groups., Conclusions: Ultrasound-guided circumferential injection of local anesthetic around the sciatic nerve at the popliteal fossa can improve the rate of sensory block without an increase in block procedure time or block-related complications compared with a single-location injection technique.

This article provides an instructive review of the essential functions universal to modern ultrasound machines in use for regional anesthesia practice. An understanding of machine knobology is integral to performing safe and successful ultrasound-guided regional anesthesia.

Objectives: The American Society of Regional Anesthesia and Pain Medicine charged an expert panel to examine the evidence basis for ultrasound guidance as a nerve localization tool in the clinical practices of regional anesthesia and interventional pain medicine., Methods: The panel searched, examined, and assessed the literature of ultrasound-guided regional anesthesia (UGRA) from the past 20 years. The qualities of studies were graded using the Jadad score. Strength of evidence and recommendations were graded using an accepted rating tool., Results: The panel made specific literature-based assessments concerning the relative advantages and limitations of UGRA relative to traditional nerve localization methods as they pertained to block characteristics and complications. Assessments and recommendations were made for upper and lower extremity, neuraxial, and truncal blocks and include pediatrics and interventional pain medicine., Conclusions: Ultrasound guidance improves block characteristics (particularly performance time and surrogate measures of success) that are often block specific and that may impart an efficiency advantage depending on individual practitioner circumstances. Evidence for UGRA impacting patient safety is currently limited to the demonstration of improvements in the frequency of surrogate events for serious complications.

Purpose: The success rate for infraclavicular brachial plexus block using nerve stimulation reportedly ranges from 60 to 80%. Ultrasound guidance may be associated with greater success. This study compared ultrasound guided infraclavicular block with a dual motor endpoint nerve stimulation technique., Methods: One hundred three hand surgery patients were randomized to receive either ultrasound-guided (ultrasound group) or dual motor endpoint nerve stimulation (stimulation group) infraclavicular block using 2% lidocaine 15 mL and 0.5% bupivacaine 15 mL with epinephrine. Block success was defined as loss of sensation to pinprick in each of the radial, ulnar, median, and musculocutaneous nerve distributions when measured 20 min after block performance. Block performance time, readiness for surgery (no supplemental block, skin infiltration, or general anesthesia), and complications were also assessed., Results: Patient characteristics were similar between groups. Success rate was 92% in the ultrasound group and 80% in the stimulation group (P = 0.18). Block performance time was shorter in the ultrasound group (median 5 min) compared with the stimulation group (median 10.5 min) (P < 0.001). Paresthesiae were more frequent in the stimulation group (45%) than in the ultrasound group (6%) (P < 0.001). After final injection, more patients were ready for surgery in the ultrasound group (85%) than in the stimulation group (65%) (P = 0.04). At 1 week postoperatively, complications were minor and transient and did not differ between groups., Conclusion: There was no statistically significant difference in the success rate between ultrasound guidance and dual motor endpoint stimulation for infraclavicular block. However, ultrasound guidance shortens performance time and improves readiness for surgery compared with dual motor endpoint stimulation.

Background and Objectives: Saphenous nerve (SN) block can be technically challenging because it is a small and exclusively sensory nerve. Traditional techniques using surface landmarks and nerve stimulation are limited by inconsistent success rates. This descriptive prospective study assesses the feasibility of performing an ultrasound-guided SN block in the distal thigh., Methods: After the research ethics board's approval and written informed consent, 20 patients undergoing ankle or foot surgery underwent ultrasonography of the medial aspect of the thigh to identify the SN in the adductor canal, as it lies adjacent to the femoral artery (FA), deep to the sartorius muscle. An insulated needle was advanced in plane under real-time guidance toward the nerve. After attempting to elicit paresthesia with nerve stimulation, 2% lidocaine with 1:200,000 epinephrine (5 mL) and 0.5% bupivacaine (5 mL) were injected around the SN., Results: The SN was identified in all patients, most frequently in an anteromedial position relative to the FA, at a depth of 2.7 +/- 0.6 cm and 12.7 +/- 2.2 cm proximal to the knee joint. Complete anesthesia in the SN distribution developed in all patients by 25 mins after injection., Conclusions: In this small descriptive study, ultrasound-guided SN block in the adductor canal was technically simple and reliable, providing consistent nerve identification and block success.

Purpose: Spinal anesthesia can be challenging in patients undergoing total joint arthroplasty because of poorly palpable surface landmarks and age-related changes in the lumbar spine. We hypothesized that pre-procedural ultrasound imaging would be effective in identifying the lumbar intervertebral spaces and would provide an accurate measure of the depth to the intrathecal space., Methods: Fifty patients undergoing elective total joint arthroplasty were recruited in this prospective descriptive study. Using a curved-array 2-5 MHz transducer, the lumbar spine was imaged in two views, i.e., longitudinal parasagittal (LP) and transverse midline (TM). The intervertebral levels were identified by counting upwards from the sacrum. The locations of the interlaminar spaces were identified by visualizing the ligamentum flavum-dura mater complex and the posterior aspect of the vertebral body. The needle insertion point for a midline approach was determined from the ultrasound examination and was marked on the skin of the patient's back., Results: The mean patient age was 67 +/- 10 yr, and 46% of the patients had a body mass index >30 kg . m(-2). Surface landmarks were difficult or impossible to palpate in 38% of the patients. The scan quality on the LP and TM views was adequate or better in 100 and 98% of the patients, respectively. Dural puncture was achieved with one needle insertion attempt and within two needle insertion attempts in 84% and 98% of the patients, respectively. The ultrasound-measured depth to the intrathecal space correlated well with the actual needle insertion depth (concordance correlation coefficient = 0.82, accuracy 0.95, precision 0.86), with a tendency to overestimate the depth by just 2.1 +/- 5.4 mm., Conclusions: Ultrasound imaging of the lumbar spine provides clinically useful information that can facilitate spinal anesthesia in the older orthopedic patient population.

Patients with permanent cardiac pacemakers (PPMs) are vulnerable to electromagnetic interference from electrical equipment used in the operating room environment. Electromagnetic interference may lead to PPM malfunction with potential harmful effects to the patient. Conventional techniques for peripheral nerve blockade include the use of electrical nerve stimulation (NS) for nerve localization. The hazards of NS, especially when applied near the implanted PPM sites, are not known. In the absence of available guidelines regarding the safe use of NS in the setting of an implanted PPM, we recommend a combined guidance approach for peripheral nerve blockade using ultrasound for nerve localization along with low-current NS for nerve identification.

Background and Objectives: The aim of this study was to determine the minimum effective anesthetic volume required to produce an effective supraclavicular block for surgical anesthesia using an ultrasound (US)-guided technique., Methods: Twenty-one adults undergoing elective upper limb surgery received a US-guided supraclavicular block. The initial volume of local anesthetic (LA; 50:50 mixture of lidocaine 2% and bupivacaine 0.5% with epinephrine) injected was 30 mL, which was subsequently varied by 5 mL for each consecutive patient according to the response of the previous patient. The minimum effective anesthetic volume in 50% of patients was determined using the Dixon and Massey up-and-down method. The effective volume in 95% of patients (ED95) was calculated using probit transformation and logistic regression., Results: The minimum effective anesthetic volume in 50% and calculated effective volume in 95% of patients were 23 mL (95% confidence interval, 13-39 mL) and 42 mL (95% confidence interval, 19-65 mL), respectively. Seven patients received supplemental LA, with no patient requiring a general anesthetic., Conclusion: In this study, the minimum volume required for US-guided supraclavicular block in 50% of patients was 23 mL, and in 95% of patients was 42 mL. Under the present study conditions, the calculated volume of LA required for US-guided supraclavicular block does not seem to differ from the conventionally recommended volume required for supraclavicular blocks using non-US-based nerve localization techniques.

Introduction: Supraclavicular brachial plexus block provides consistently effective anesthesia to the upper extremity. However, traditional nerve localization techniques may be associated with a high risk of pneumothorax. In the present study, we report block success and clinical outcome data from 510 consecutive patients who received an ultrasound-guided supraclavicular block for upper extremity surgery., Methods: After institutional review board approval, the outcome of 510 consecutive patients who received an ultrasound-guided supraclavicular block for upper extremity surgery was reviewed. Real-time ultrasound guidance was used with a high-frequency linear probe. The neurovascular structures were imaged on short axis, and the needle was inserted using an in-plane technique with either a medial-to-lateral or lateral-to-medial orientation., Results: Five hundred ten ultrasound-guided supraclavicular blocks were performed (50 inpatients, 460 outpatients) by 47 different operators at different levels of training over a 24-month period. Successful surgical anesthesia was achieved in 94.6% of patients after a single attempt; 2.8% required local anesthetic supplementation of a single peripheral nerve territory; and 2.6% received an unplanned general anesthetic. No cases of clinically symptomatic pneumothorax developed. Complications included symptomatic hemidiaphragmatic paresis (1%), Horner syndrome (1%), unintended vascular punctures (0.4%), and transient sensory deficits (0.4%)., Conclusions: Ultrasound-guided supraclavicular block is associated with a high rate of successful surgical anesthesia and a low rate of complications and thus may be a safe alternative for both inpatients and outpatients. Severe underlying respiratory disease and coagulopathy should remain a contraindication for this brachial plexus approach.

Background and Objectives: The presence of neurovascular abnormalities may increase the risk of complications following regional anesthesia techniques. Use of conventional nerve localization methods may fail to detect such abnormalities and potentially result in block failure and/or unintentional neurovascular injury., Methods: We use 2 examples to illustrate this, and the concept that systematic use of a preprocedure ultrasound (US) scan may serve as an aid both for diagnosis of abnormal anatomy, and in planning the appropriate anesthetic technique., Results: Use of a preprocedure US scan helped to diagnose abnormal anatomy and assisted in planning a more appropriate anesthetic technique., Conclusions: We believe that a systematic sonographic survey prior to regional anesthesia can be a valuable bedside screening tool to assess the suitability and challenges involved in performing US-guided peripheral nerve block.

Needle visualization is important for safe and successful ultrasound-guided peripheral nerve block. However, accurate and consistent visualization of the needle tip can be difficult to achieve. This review article describes many of the challenges affecting needle visualization, summarizes the relevant literature on ultrasound imaging of needles, and offers practical strategies for improving needle tip visibility. Finally, future directions for research and development are suggested.

Background and Objectives: Real time ultrasound guidance is a recent development in the area of peripheral nerve blockade. There are limited data from prospective randomized trials comparing its efficacy to that of traditional nerve localization techniques. In the present study, we tested the hypothesis that ultrasound guidance improves the success rate of sciatic nerve block at the popliteal fossa when compared with a nerve stimulator-guided technique., Methods: After Institutional Research Ethics Board approval and informed consent, 74 patients undergoing elective major foot or ankle surgery were randomly assigned to receive a sciatic nerve block at the popliteal fossa guided by either ultrasonography (group US, transverse view, needle in plane approach above the sciatic nerve bifurcation), or nerve stimulation (group NS, single injection, 10 cm proximal to the knee crease). A standardized local anesthetic admixture (15 mL of 2% lidocaine with 1:200,000 epinephrine and 15 mL of 0.5% bupivacaine) was used. Sensory and motor function was assessed by a blinded observer at predetermined intervals for up to 1 hour. Block success was defined as a loss of sensation to pinprick within 30 minutes in the distribution of both tibial and common peroneal nerves., Results: Group US had a significantly higher block success rate than group NS (89.2% vs. 60.6%, P = .005), while the procedure time was similar., Conclusions: Ultrasound guidance enhances the quality of popliteal sciatic nerve block compared with single injection, nerve stimulator-guided block using either a tibial or peroneal endpoint. Ultrasound guidance resulted in higher success, faster onset, and progression of sensorimotor block, without an increase in block procedure time, or complications.

Purpose: The purpose of this study is to determine if real time ultrasound guidance improves the success rate of axillary brachial plexus blockade., Methods: Patients undergoing elective hand surgery were randomly assigned to one of three groups. Axillary blocks were performed using three motor response endpoints in the nerve stimulator (NS) Group, real-time ultrasound guidance in the ultrasound (US) Group and combined ultrasound and nerve stimulation in the USNS Group. Following administration of a standardized solution containing 2% lidocaine with 1:200,000 epinephrine and 0.5% bupivacaine (total 42 mL), sensory and motor functions were assessed by a blinded observer every five minutes for 30 min. A successful block was defined as complete sensory loss in the median, radial and ulnar nerve distribution by 30 min. The need for local and general anesthesia supplementation and post-block adverse events were documented., Results: One hundred and eighty-eight patients completed the study. Block success rate was higher in Groups US and USNS (82.8% and 80.7%) than Group NS (62.9%) (P = 0.01 and 0.03 respectively). Fewer patients in Groups US and USNS required supplemental nerve blocks and/or general anesthesia. Postoperatively, axillary bruising and pain were reported more frequently in Group NS., Conclusion: This study demonstrates that ultrasound guidance, with or without concomitant nerve stimulation, significantly improves the success rate of axillary brachial plexus block.

Purpose of Review: This article introduces the use of ultrasound to facilitate peripheral regional anesthesia., Recent Findings: Regional anesthesia, despite its well known clinical benefits, has not gained the popularity of general anesthesia. This is secondary to multiple shortcomings including a defined failure rate, lack of simplicity, and the potential for patient discomfort or injury. Many of the negative aspects of regional anesthesia evolve from the reality that current nerve-localization techniques are unreliable. Given the great variation in human anatomy it is not surprising that even the most veteran clinician can be challenged by techniques that demand anatomical assumptions. The recent use of ultrasound imaging for nerve localization is an innovative application of an old technology which addresses many of the shortcomings of current techniques. Specifically, ultrasound imaging allows the operator to see neural structures, guide the needle under real-time visualization, navigate away from sensitive anatomy, and monitor the spread of local anesthetic., Summary: Ultrasound technology represents an ideal mechanism by which the regional anesthesiologist can attain the safety, speed, and efficacy of general anesthesia. Ultimately, it is the correct peri-neural spread of local anesthetic around a nerve that provides safe, effective, and efficient anesthetic conditions.