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.

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.

Incidental detection of bowel herniation with ultrasonography and fluoroscopy during a caudal block.

BACKGROUND: In contrast to fluoroscopy, ultrasonography allows visualization of structures such as muscles, tendons, vessels, and nerves. We describe a case where ultrasonography in conjunction with fluoroscopy led to the incidental diagnosis of bowel herniation in a patient undergoing a caudal block. CLINICAL FEATURES: A 71-yr-old woman presented to our chronic pain clinic with a long-standing history of coccydynia for which she had undergone a partial coccygectomy. A trial caudal block was planned. Fluoroscopy of the lower sacral area revealed the presence of a gas bubble inferoposteriorly to the coccygeal remnant. A confirmatory ultrasound scan revealed a hollow structure compatible with bowel. The procedure was abandoned. Subsequently, a non-enhanced computed tomographic scan of the pelvis confirmed the diagnosis of large bowel herniation. The patient was referred to a colorectal surgeon, and she subsequently underwent successful laparoscopic repair of the coccygeal hernia. CONCLUSION: Ultrasonography can be a valuable adjunct in identifying non-neural pathologies in patients undergoing interventional procedures in chronic pain management. This case report highlights the importance of being vigilant for unanticipated pathologies during ultrasound examinations while performing chronic pain block procedures.

Lumbar spinal stenosis: a brief review of the nonsurgical management.

PURPOSE: The purpose of this brief narrative review is to summarize the evidence derived from randomized controlled trials pertaining to the nonsurgical treatment of lumbar spinal stenosis (LSS). SOURCE: The MEDLINE (January 1950 to the fourth week of January 2010) and EMBASE (January 1980 to 2009, week 53) databases, the MESH term "spinal stenosis", and the key words, "vertebral canal stenosis" and "neurogenic claudication", were searched. Results were limited to randomized controlled trials (RCTs) conducted on human subjects, written in English, and published in peer-reviewed journals. Only RCTs pertaining to nonsurgical treatment were considered. Studies comparing conservative and surgical management or different surgical techniques were not included in the review. PRINCIPAL FINDINGS: The search criteria yielded 13 RCTs. The average enrolment was 54 subjects per study. Blinded assessment and sample size justification were provided in 85% and 39% of RCTs, respectively. The available evidence suggests that parenteral calcitonin, but not intranasal calcitonin, can transiently decrease pain in patients with LSS. In the setting of epidural blocks, local anesthetics can improve pain and function, but the benefits seem short-lived. The available evidence does not support the addition of steroids to local anesthetic agents. Based on the limited evidence, passive physical therapy seems to provide minimal benefits in LSS. The optimal regimen for active physiotherapy remains unknown. Although benefits have been reported with gabapentin, limaprost, methylcobalamin, and epidural adhesiolysis, further trials are required to validate these findings. CONCLUSIONS: Because of their variable quality, published RCTs can provide only limited evidence to formulate recommendations pertaining to the nonsurgical treatment of LSS. In this narrative review, no study was excluded based on factors such as sample size justification, statistical power, blinding, definition of intervention allocation, or clinical outcomes. This aspect may represent a limitation as it may serve to overemphasize evidence derived from "weaker" trials. Further well-designed RCTs are warranted.

Treatment of complex regional pain syndrome: a review of the evidence.

PURPOSE: This narrative review summarizes the evidence derived from randomized controlled trials pertaining to the treatment of complex regional pain syndrome (CRPS). SOURCE: Using the MEDLINE (January 1950 to April 2009) and EMBASE (January 1980 to April 2009) databases, the following medical subject headings (MeSH) were searched: "Complex Regional Pain Syndrome", "Reflex Sympathetic Dystrophy", and "causalgia" as well as the key words "algodystrophy", "Sudeck's atrophy", "shoulder hand syndrome", "neurodystrophy", "neuroalgodystrophy", "reflex neuromuscular dystrophy", and "posttraumatic dystrophy". Results were limited to randomized controlled trials (RCTs) conducted on human subjects, written in English, published in peer-reviewed journals, and pertinent to treatment. PRINCIPAL FINDINGS: The search criteria yielded 41 RCTs with a mean of 31.7 subjects per study. Blinded assessment and sample size justification were provided in 70.7% and 19.5% of RCTs, respectively. Only biphosphonates appear to offer clear benefits for patients with CRPS. Improvement has been reported with dimethyl sulfoxide, steroids, epidural clonidine, intrathecal baclofen, spinal cord stimulation, and motor imagery programs, but further trials are required. The available evidence does not support the use of calcitonin, vasodilators, or sympatholytic and neuromodulative intravenous regional blockade. Clear benefits have not been reported with stellate/lumbar sympathetic blocks, mannitol, gabapentin, and physical/occupational therapy. CONCLUSIONS: Published RCTs can only provide limited evidence to formulate recommendations for treatment of CRPS. In this review, no study was excluded based on factors such as sample size justification, statistical power, blinding, definition of intervention allocation, or clinical outcomes. Thus, evidence derived from "weaker" trials may be overemphasized. Further well-designed RCTs are warranted.

A comparison between ultrasound-guided infraclavicular block using the "double bubble" sign and neurostimulation-guided axillary block.

BACKGROUND: Ultrasound-guided infraclavicular block can be performed using the double bubble sign. Previously described, the double bubble sign consists superiorly of the axillary artery (in short axis) superimposed on an inferior bubble created by local anesthetic injection. In this study, we compared this new method of brachial plexus anesthesia to the traditional triple-nerve stimulation axillary block. METHODS: Seventy patients were randomized to receive a single-injection, ultrasound-guided infraclavicular block using the double bubble sign or a triple-stimulation axillary block. RESULTS: Both methods produced similar success rates (89%-91%). However, infraclavicular blocks were associated with a shorter performance time (3.90 +/- 2.27 vs 8.03 +/- 3.92 min; P < 0.001) and lower block-related pain scores (2.70 +/- 2.02 vs 4.17 +/- 2.57 on a 0-10 scale; P = 0.01). CONCLUSION: Compared to triple-stimulation axillary block, ultrasound-guided infraclavicular block using the double bubble sign provided a similar efficacy, a shorter performance time and lower procedural pain scores.

Minimal threshold for stimulating catheters.

A patient undergoing total knee replacement was fitted with a stimulating femoral catheter for postoperative analgesia. After the catheter was secured to the skin, the minimal stimulatory threshold was verified again and found to be extremely low (0.00-0.01 mA; pulse width, 0.1 ms). However, in spite of this situation, no paresthesia or pain was experienced by the patient. Use of the catheter resulted in satisfactory analgesia with no complications noted during the hospital stay or at follow-up three months later. When the nerve stimulator was sent to our biomedical engineering department to verify the accuracy of its current output, it was found to be functioning adequately. Neurostimulation is a complex phenomenon that is far from being completely understood. On the basis of this single report, we cannot recommend the routine use of a threshold inferior to 0.2 mA for neural electrolocation. However, we do not advocate the requirement of strict numerical thresholds either. Further research is needed to understand the relationship linking stimulatory threshold and distance between needle (or catheter) tip and nerve.

Electrical stimulation of the epidural space using a catheter with a removable stylet.

BACKGROUND AND OBJECTIVES: Electrical stimulation can be used to verify the location of epidural catheters. With the traditional technique, the latter must be primed with saline to allow for electrical conduction: any air lock will, thus, hinder the flow of current. Therefore, we set out to explore an alternative mode of stimulation by use of a catheter containing a removable stylet. This study examines the reliability of this new technique. METHODS: In 71 patients undergoing surgery, a thoracic epidural catheter was inserted preoperatively. Loss of resistance was used to identify the epidural space. The TheraCath was introduced 5 cm into the space and connected to a neurostimulator via a 2-headed alligator clip. The intensity, pulse width, and level of myotomal contractions were recorded upon stimulation of the epidural space. A bolus of lidocaine was then injected and the patient assessed for sensory block to ice. RESULTS: The failure rate in proper epidural catheter placement was 8.5%. Epidural stimulation yielded a mean threshold of 1.90 +/- 1.80 nanocoulombs. A total of 37 catheters produced a unilateral muscular response; however, block to ice was bilateral. When compared with the ice test, the sensitivity, specificity, positive predictive value, and negative predictive value of epidural stimulation with the TheraCath were 92%, 83%, 98%, and 50%, respectively. CONCLUSION: We conclude that the TheraCath, because of the removable stylet, provides effective electrostimulation of the epidural space. Its use was simple and devoid of complications. Nonetheless, further studies are required before implementing its routine use in clinical settings.

Diaphragm-Sparing Nerve Blocks for Shoulder Surgery.

Shoulder surgery can result in significant postoperative pain. Interscalene brachial plexus blocks (ISBs) constitute the current criterion standard for analgesia but may be contraindicated in patients with pulmonary pathology due to the inherent risk of phrenic nerve block and symptomatic hemidiaphragmatic paralysis. Although ultrasound-guided ISB with small volumes (5 mL), dilute local anesthetic (LA) concentrations, and LA injection 4 mm lateral to the brachial plexus have been shown to reduce the risk of phrenic nerve block, no single intervention can decrease its incidence below 20%. Ultrasound-guided supraclavicular blocks with LA injection posterolateral to the brachial plexus may anesthetize the shoulder without incidental diaphragmatic dysfunction, but further confirmatory trials are required. Ultrasound-guided C7 root blocks also seem to offer an attractive, diaphragm-sparing alternative to ISB. However, additional large-scale studies are needed to confirm their efficacy and to quantify the risk of periforaminal vascular breach. Combined axillary-suprascapular nerve blocks may provide adequate postoperative analgesia for minor shoulder surgery but do not compare favorably to ISB for major surgical procedures. One intriguing solution lies in the combined use of infraclavicular brachial plexus blocks and suprascapular nerve blocks. Theoretically, the infraclavicular approach targets the posterior and lateral cords, thus anesthetizing the axillary nerve (which supplies the anterior and posterior shoulder joint), as well as the subscapular and lateral pectoral nerves (both of which supply the anterior shoulder joint), whereas the suprascapular nerve block anesthetizes the posterior shoulder. Future randomized trials are required to validate the efficacy of combined infraclavicular-suprascapular blocks for shoulder surgery.

Ultrasound-Guided Cervical Medial Branch Radiofrequency Neurotomy: Can Multitined Deployment Cannulae Be the Solution?

BACKGROUND AND OBJECTIVES: Novel multitined cannulae constitute an attractive option for ultrasound-guided radiofrequency neurotomy of cervical medial branches. The deployment tines increase the cannula's active area, thus altering its lesion size. Despite their theoretical benefits, multitined cannulae have not been assessed. In this bench study, we sought to investigate the lesions produced by a standard 18-gauge and 2 commercially available multitined deployment cannulae. We created ex vivo models to evaluate lesion morphology at a periosteal interface using approach angles likely to be encountered during an ultrasound-guided technique. METHODS: Two ex vivo models were assembled using chicken breast tissue and bovine tibia. Monopolar lesions were carried out with 3 commercially available cannulae (18-gauge curved [S], 17-gauge with laterally deploying tines [N], and 18-gauge with distally deploying tines [T]). All cannulae were positioned at 0, 25, 45, and 90 degrees to the periosteal plane. For each angulation and cannula, 2 series of measurements were recorded to document lesion morphology in the axial and sagittal planes. Data collected included the lesion's surface area, shape, and dimensions relative to the needle tip. RESULTS: A total of 240 lesions were analyzed. The performances of S and N cannulae were significantly affected by approach angle, with lesion size decreasing as the angle increased. In contrast, T cannulae displayed similar lesion surface areas at 0 and 90 degrees. The multitined N and T cannulae produced the largest lesions at 0/25 and 90 degrees, respectively. Lesion height varied inversely according to approach angle for S and N cannulae, whereas T cannulae displayed stable characteristics. CONCLUSIONS: Unlike their S and N counterparts, T cannulae demonstrated stable lesion characteristics at varying approach angles.

Primary Failure of Thoracic Epidural Analgesia in Training Centers: The Invisible Elephant?

In teaching centers, primary failure of thoracic epidural analgesia can be due to multiple etiologies. In addition to the difficult anatomy of the thoracic spine, the conventional end point-loss-of-resistance-lacks specificity. Furthermore, insufficient training compounds the problem: learning curves are nonexistent, pedagogical requirements are often inadequate, supervisors may be inexperienced, and exposure during residency is decreasing. Any viable solution needs to be multifaceted. Learning curves should be explored to determine the minimal number of blocks required for proficiency. The problem of decreasing caseload can be tackled with epidural simulators to supplement in vivo learning. From a technical standpoint, fluoroscopy and ultrasonography could be used to navigate the complex anatomy of the thoracic spine. Finally, correct identification of the thoracic epidural space should be confirmed with objective, real-time modalities such as neurostimulation and waveform analysis.

A Randomized Comparison Between Conventional and Waveform-Confirmed Loss of Resistance for Thoracic Epidural Blocks.

BACKGROUND AND OBJECTIVES: Epidural waveform analysis (EWA) provides a simple confirmatory adjunct for loss of resistance (LOR): when the needle tip is correctly positioned inside the epidural space, pressure measurement results in a pulsatile waveform. In this randomized trial, we compared conventional and EWA-confirmed LOR in 2 teaching centers. Our research hypothesis was that EWA-confirmed LOR would decrease the failure rate of thoracic epidural blocks. METHODS: One hundred patients undergoing thoracic epidural blocks for thoracic surgery, abdominal surgery, or rib fractures were randomized to conventional LOR or EWA-LOR. The operator was allowed as many attempts as necessary to achieve a satisfactory LOR (by feel) in the conventional group. In the EWA-LOR group, LOR was confirmed by connecting the epidural needle to a pressure transducer using a rigid extension tubing. Positive waveforms indicated that the needle tip was positioned inside the epidural space. The operator was allowed a maximum of 3 different intervertebral levels to obtain a positive waveform. If waveforms were still absent at the third level, the operator simply accepted LOR as the technical end point. However, the patient was retained in the EWA-LOR group (intent-to-treat analysis).After achieving a satisfactory tactile LOR (conventional group), positive waveforms (EWA-LOR group), or a third intervertebral level with LOR but no waveform (EWA-LOR group), the operator administered a 4-mL test dose of lidocaine 2% with epinephrine 5 µg/mL. Fifteen minutes after the test dose, a blinded investigator assessed the patient for sensory block to ice. RESULTS: Compared with LOR, EWA-LOR resulted in a lower rate of primary failure (2% vs 24%; P = 0.002). Subgroup analysis based on experience level reveals that EWA-LOR outperformed conventional LOR for novice (P = 0.001) but not expert operators. The performance time was longer in the EWA-LOR group (11.2 ± 6.2 vs 8.0 ± 4.6 minutes; P = 0.006). Both groups were comparable in terms of operator's level of expertise, depth of the epidural space, approach, and LOR medium. In the EWA-LOR group, operators obtained a pulsatile waveform with the first level attempted in 60% of patients. However, 40% of subjects required performance at a second or third level. CONCLUSIONS: Compared with its conventional counterpart, EWA-confirmed LOR results in a lower failure rate for thoracic epidural blocks (2% vs 24%) in our teaching centers. Confirmatory EWA provides significant benefits for inexperienced operators.

Real-Time Detection of Periforaminal Vessels in the Cervical Spine: An Ultrasound Survey.

BACKGROUND AND OBJECTIVES: Compared with the thoracic and lumbar spine, transforaminal epidural injections and medial branch blocks in the cervical spine are associated with a higher incidence of neurological complications. Accidental breach of small periforaminal arteries has been implicated in many instances. In this observational study, using ultrasonography, we surveyed the incidence of periforaminal bloods vessels in the cervical spine. METHODS: Patients undergoing ultrasound-guided cervical medial branch blocks were scanned using color power and pulsed wave Doppler. Five levels from C2/C3 to C6/C7 were studied. Incidental blood vessels located between the anterior tubercles of the transverses process and the posterior borders of the articular pillars were included for analysis. We recorded the diameter and position of arteries relative to contiguous bony landmarks as well the number of veins. RESULTS: In 102 patients, we performed a total 201 scans (1005 cervical levels). Of the 363 incidental vessels identified, 238 were arteries (mean diameter, 1.25 ± 0.45 mm). The latter were most commonly found at the posterior foraminal aspects of C5, C6, and C7 (13%, 11%, and 16% of scans, respectively); the transverse processes of C5 and C6 (10% and 16% of scans, respectively); and the articular pillars of C6 and C7 (19% and 16% of scans, respectively). CONCLUSIONS: Small periforaminal arteries are prevalent along the lateral aspect of the cervical spine, adjacent to areas commonly targeted by nerve block procedures. Further trials are required to determine if ultrasound guidance can reduce the incidence of complications related to accidental vascular breach.

A Multicenter Randomized Comparison Between Intravenous and Perineural Dexamethasone for Ultrasound-Guided Infraclavicular Block.

BACKGROUND AND OBJECTIVES: This multicenter, randomized trial compared intravenous (IV) and perineural (PN) dexamethasone for ultrasound (US)-guided infraclavicular brachial plexus block. Our research hypothesis was both modalities would result in similar durations of motor block. METHODS: One hundred fifty patients undergoing upper limb surgery with US-guided infraclavicular block were randomly allocated to receive IV or PN dexamethasone (5 mg). The local anesthetic agent (35 mL of lidocaine 1%-bupivacaine 0.25% with epinephrine 5 µg/mL) was identical in all subjects. Patients and operators were blinded to the nature of IV and PN injectates. During the performance of the block, the performance time, number of needle passes, procedural pain, and complications (vascular puncture, paresthesia) were recorded.Subsequently, a blinded observer assessed the success rate (defined as a minimal sensorimotor composite score of 14 of 16 points at 30 minutes), onset time as well as the incidence of surgical anesthesia (defined as the ability to complete surgery without local infiltration, supplemental blocks, IV opioids, or general anesthesia). Postoperatively (at 24 hours), the blinded observer contacted patients with successful blocks to enquire about the duration of motor block, sensory block, and postoperative analgesia. The main outcome variable was the duration of motor block. RESULTS: No intergroup differences were observed in terms of technical execution (performance time/number of needle passes/procedural pain/complications), onset time, success rate, and surgical anesthesia. However, compared to its IV counterpart, PN dexamethasone provided 19% to 22% longer durations for motor block (15.7 ± 6.2 vs 12.9 ± 5.5 hours; P = 0.009), sensory block (16.8 ± 4.4 vs 13.9 ± 5.4 hours; P = 0.002), and postoperative analgesia (22.1 ± 8.5 vs 18.6 ± 6.7 hours; P = 0.014). CONCLUSIONS: Compared with its IV counterpart, PN dexamethasone (5 mg) provides a longer duration of motor block, sensory block, and postoperative analgesia for US-guided infraclavicular block. Future dose-finding studies are required to elucidate the optimal dose of dexamethasone.

Use of stellate ganglion block to salvage an ischemic hand caused by the extravasation of vasopressors.

OBJECTIVE: This case report describes the successful use of early stellate ganglion block to salvage an acutely ischemic hand caused by the extravasation of vasopressors. CASE REPORT: A young man with a gunshot wound to the right inguinal area was brought to the operating room for surgical hemostasis and exploration. After discovery that the central line had been inserted in the proximity of the area of injury (right femoral vein), the vasopressor infusions were changed to a 14-gauge intravenous line inserted in the dorsum of the right hand. When the intravenous line became infiltrated, the hand was found to be swollen, cold, and underperfused. A right stellate ganglion block was immediately performed to overcome the intense peripheral vasoconstriction and, thus, re-establish circulation to the hand. CONCLUSIONS: Stellate ganglion block may prove to be an early measure in the treatment of upper-extremity ischemia caused by vasopressor extravasation.