Brachial plexus examination and localization using ultrasound and electrical stimulation: a volunteer study

BACKGROUND: Current techniques of brachial plexus block are "blind," and nerve localization can be frustrating and time consuming. Previous studies on ultrasound-assisted brachial plexus blocks are mostly performed with scanning probes of 10 MHz or less. The authors tested the usefulness of a state-of-the-art, high-resolution ultrasound probe (up to 12 MHz) in identifying the brachial plexus in five locations of the upper extremity and in guiding needle advancement to target before nerve stimulation. METHODS: In this prospective observational study, 15 volunteers underwent brachial plexus examination using an L12-L5 MHz probe and a Philips-ATL 5000 ultrasound unit in the interscalene, supraclavicular, infraclavicular, axillary, and midhumeral regions. Thereafter, an insulated block needle was advanced under direct ultrasound guidance to target nerves before confirmation by electrical nerve stimulation in five volunteers in each of the interscalene, supraclavicular, and axillary regions. The quality of brachial plexus images, anatomic variations, and the technique of needle advancement for nerve localization were recorded. RESULTS: The brachial plexus components were successfully identified in the transverse view as round to oval hypoechoic structures with small internal punctuate echos in all regions examined except the infraclavicular area (visualized in 27% of the cases). The authors' technique of advancing the needle in-line with the ultrasound beam allowed moment-by-moment observation of the needle shaft and tip movement at the time of nerve localization. Hypoechoic structures were stimulated electrically and confirmed to be nerves. CONCLUSIONS: These preliminary data show that the high-resolution L12-L5 probe provides good quality brachial plexus ultrasound images in the superficial locations i.e., the interscalene, supraclavicular, axillary, and midhumeral regions. The needle technique described here for ultrasound-assisted nerve localization provides real-time guidance and is potentially valuable for brachial plexus blocks.     

Brachial Plexus Examination and Localization Using Ultrasound and Electrical Stimulation: A Volunteer Study

Background: Current techniques of brachial plexus block are "blind," and nerve localization can be frustrating and time consuming. Previous studies on ultrasound-assisted brachial plexus blocks are mostly performed with scanning probes of 10 MHz or less. The authors tested the usefulness of a state-of-the-art, high-resolution ultrasound probe (up to 12 MHz) in identifying the brachial plexus in five locations of the upper extremity and in guiding needle advancement to target before nerve stimulation.

Methods: In this prospective observational study, 15 volunteers underwent brachial plexus examination using an L12-L5 MHz probe and a Philips-ATL 5000 ultrasound unit in the interscalene, supraclavicular, infraclavicular, axillary, and midhumeral regions. Thereafter, an insulated block needle was advanced under direct ultrasound guidance to target nerves before confirmation by electrical nerve stimulation in five volunteers in each of the interscalene, supraclavicular, and axillary regions. The quality of brachial plexus images, anatomic variations, and the technique of needle advancement for nerve localization were recorded.

Results: The brachial plexus components were successfully identified in the transverse view as round to oval hypoechoic structures with small internal punctuate echos in all regions examined except the infraclavicular area (visualized in 27% of the cases). The authors' technique of advancing the needle in-line with the ultrasound beam allowed moment-by-moment observation of the needle shaft and tip movement at the time of nerve localization. Hypoechoic structures were stimulated electrically and confirmed to be nerves.     

Supraclavicular brachial plexus blocks: review and current practice

This article reviews the possible revival of the supraclavicular brachial plexus blockade due to the use of ultrasound guidance. The brachial plexus is a complex network of nerves, extending from the neck to the axilla, which supplies motor and sensory fibers to the upper extremity. Understanding the complexities of the formation and structure of the brachial plexus remains a cornerstone for effective regional anaesthesia. On the level of the supraclavicular fossa, the plexus is most compactly arranged. The supraclavicular approach of the brachial plexus has a high success rate including blockade of the ulnar and musculocutaneous nerve, which can be missed respectively with the interscalene and axillary approach. However, because of the proximity of the pleura, most anaesthesiologists have been reluctant to perform this supraclavicular approach. The introduction of ultrasound guidance techniques not only reduces the possible risk of pneumothorax but also allows a faster onset time of the block with a reduction of the local anaesthetic dose. This makes the supraclavicular approach a valuable alternative to the axillary, interscalene and infraclavicular approach for upper limb surgery.     

The pharmacokinetics of ropivacaine after four different techniques of brachial plexus blockade

Arterial plasma concentrations of ropivacaine were measured after brachial plexus blockade using four different approaches: lateral interscalene (Winnie), posterior interscalene (Pippa), axillary and vertical infraclavicular. Four groups of 10 patients were given a single 3.75 mg.kg(-1) injection of ropivacaine 7.5 mgxml(-1). The pharmacokinetics of ropivacaine were evaluated for 1 h after local anaesthetic injection. The supraclavicular techniques (lateral and posterior) were associated with earlier and higher peak plasma concentrations of local anaesthetic than the infraclavicular techniques (axillary and vertical infraclavicular): mean (SD) values = 3.30 (0.65) microgxml(-1) vs 2.55 (0.62) microgxml(-1) (p = 0.001) in 13.4 (6.9) min vs 25.0 (10.8) min (p = 0.0002). More ropivacaine is taken up by the systemic circulation in the first hour after the supraclavicular approaches; the mean (SD) area under the concentration-time curve was larger: 2.63 (0.51) microgxml(-1).h vs 2.10 (0.49) microgxml(-1).h (p = 0.002). These results show that the technique used for brachial plexus blockade significantly influences the systemic uptake of ropivacaine.     

Restricted infraclavicular distribution of the local anesthetic solution after infraclavicular brachial plexus block

BACKGROUND AND OBJECTIVES: The distribution of local anesthetic after different approaches for brachial plexus anesthesia could be responsible for the varying rates of side effects, such as phrenic block, hoarseness, and Horner's syndrome associated with each approach. We compared the distribution of local anesthetic within the neurovascular space in infraclavicular block with that of interscalene and supraclavicular block. METHODS: In a prospective analysis using fluoroscopy, we studied the distribution of a solution of local anesthetic containing radiologic contrast medium in 18 patients. Six patients received an interscalene block, another 6 patients received a perpendicular supraclavicular block, and another 6 patients, a perpendicular coracoid block. RESULTS: Distribution of the anesthetic solution in the interscalene and supraclavicular groups extended to both supraclavicular and infraclavicular spaces in all patients. This distribution was significantly different (P <.05) compared with that of the infraclavicular group. In this group, the solution remained below the clavicle in every patient. CONCLUSIONS: Spread of the local anesthetic from the infraclavicular space after infraclavicular coracoid block appears to be limited to below the level of the clavicle. Conversely, local anesthetic solution passes below the clavicle in all patients given interscalene or supraclavicular blocks.     

Ultrasound-guided regional anesthesia for upper limb surgery

Purpose

The purpose of this module is to review the main ultrasound-guided approaches used for regional anesthesia of the upper limb.

Principal findings

The anatomical configuration of the upper limb, with nerves often bundled around an artery, makes regional anesthesia of the arm both accessible and reliable. In-depth knowledge of upper limb anatomy is required to match the blocked territory with the surgical area. The interscalene block is the approach most commonly used for shoulder surgery. Supraclavicular, infraclavicular, and axillary blocks are indicated for elbow and forearm surgery. Puncture techniques have evolved dramatically with ultrasound guidance. Instead of targeting the nerves directly, it is now recommended to look for diffusion areas. Typically, local anesthetics are deposited around vessels, often as a single injection. Phrenic nerve block can occur with the interscalene and supraclavicular approaches. Ulnar nerve blockade is almost never achieved with the interscalene approach and not always present with a supraclavicular block. If ultrasound guidance is used, the risk for pneumothorax with a supraclavicular approach is reduced significantly. Nerve damage and vascular puncture are possible with all approaches. If an axillary approach is chosen, the consequences of vascular puncture can be minimized because this site is compressible.

Conclusions

Upper limb regional anesthesia has gained in popularity because of its effectiveness and the safety profile associated with ultrasound-guided techniques.     

Efficacy of vertical infraclavicular plexus block vs. modified axillary plexus block: a prospective, randomized, observer-blinded study

BACKGROUND: Despite containing severe risks, infraclavicular approaches to the brachial plexus gained increasing popularity. Likewise, the vertical infraclavicular plexus block improved anesthesia compared to the standard axillary approach but contains the risk of pneumothorax. Therefore we modified the standard axillary technique by inserting a proximal directed catheter, referred to as a high axillary plexus block. We prospectively compared quality and onset of neural blockade after vertical infraclavicular plexus block (VIP) and high axillary plexus block (HAP) in two randomized groups (30 patients in each). METHODS: In group VIP the insulated needle was inserted midway between the ventral process of the acromion and the jugular notch. In group HAP, first an axillary needle was placed. Through this a stimulating catheter was inserted in a proximal direction (10-15 cm); correct placement was confirmed by nerve stimulation. All patients received 40 ml ropivacaine 0.75% (300 mg). Discriminating between analgesia and anesthesia, a blinded observer assessed progression of neural blockade every 5 min for 60 min by pin prick. Incomplete blocks were supplemented 60 min after initial injection. RESULTS: All patients in both groups demonstrated sufficient surgical anesthesia. No patient needed systemic supplementation or general anesthesia. However, vertical infraclavicular plexus block indicated superior anesthesia compared to high axillary plexus block, regarding musculocutaneous, axillary and radial nerve, which were completely blocked with a higher success rate and in a shorter time interval (P < 0.05). CONCLUSIONS: While both techniques provide sufficient surgical anesthesia, vertical infraclavicular plexus block demonstrated a partially higher success rate and a faster onset than high axillary plexus block.     

Outpatient regional anesthesia for upper extremity surgery update (2005 to present) distal to shoulder

Multiple different approaches to the brachial plexus are available for the regional anesthesiologist to provide successful anesthesia and analgesia for ambulatory surgery of the upper extremity. Although supraclavicular and infraclavicular blocks are faster to perform than axillary blocks, the operator needs to keep in mind that blocks performed around the clavicle carry the risk for specific side effects and complications, no matter whether ultrasound or nerve stimulation is the chosen modality for neurolocation. Owing to the ambulatory nature of the planned surgical intervention, even significant side effects may not become clinically symptomatic until the patient is discharged from the facility. For example, due to pneumothorax risks, axillary or mid-humeral blocks remain the most logical approaches for ambulatory surgical procedures at and below the elbow, while reserving infra-clavicularor supraclavicular approaches for surgery from the proximal humerus to above the elbow. Smaller interventions such as carpal tunnel release or trigger finger release can be performed under elbow, wrist, or digital blocks. The regional anesthesiologist should strive to develop a tailored plan for each individual case to provide the most effective and safest nerve block technique for their patients.     

Severe respiratory failure after infraclavicular block with 0.75% ropivacaine: a case report

Upper extremity surgery is usually performed with an axillary block. There is a risk of pneumothorax and phrenic nerve block when interscalene or supraclavicular block are used in day case surgery, or in patients with chronic obstructive pulmonary disease. The infraclavicular block is a simple, reliable, and easy to learn method to block the brachial plexus. No clinically relevant respiratory effects have been reported with infraclavicular block. Nonetheless, we report a case of a chronic obstructive pulmonary disease patient who developed severe respiratory failure requiring tracheal intubation after an infraclavicular block.     

Brachial plexus blocks for upper extremity orthopaedic surgery

Regional anesthesia of the upper extremity has several clinical applications and is reported to have several advantages over general anesthesia for orthopaedic surgery. These advantages, such as improved postoperative pain, decreased postoperative opioid administration, and reduced recovery time, have led to widespread acceptance of a variety of regional nerve blocks. Interscalene block is the most commonly used block for shoulder surgery. Other brachial plexus nerve blocks used for orthopaedic surgery of the upper extremity are supraclavicular, infraclavicular, and axillary. Several practical and theoretical aspects of regional nerve blocks must be considered to optimize the beneficial effects and minimize the risk of complications.     

A review of approaches and techniques for lower extremity nerve blocks

PURPOSE: The purpose of this narrative review is to summarize the evidence derived from randomized controlled trials (RCTs) regarding approaches and techniques for lower extremity nerve blocks. SOURCE: Using the MEDLINE (January 1966 to April 2007) and EMBASE (January 1980 to April 2007) databases, medical subject heading (MeSH) terms "lumbosacral plexus", "femoral nerve", "obturator nerve", "saphenous nerve", "sciatic nerve", "peroneal nerve" and "tibial nerve" were searched and combined with the MESH term "nerve block" using the operator "and". Keywords "lumbar plexus", "psoas compartment", "psoas sheath", "sacral plexus", "fascia iliaca", "three-in-one", "3-in-1", "lateral femoral cutaneous", "posterior femoral cutaneous", "ankle" and "ankle block" were also queried and combined with the MESH term "nerve block". The search was limited to RCTs involving human subjects and published in the English language. Forty-six RCTs were identified. PRINCIPAL FINDINGS: Compared to its anterior counterpart (3-in-1 block), the posterior approach to the lumbar plexus is more reliable when anesthesia of the obturator nerve is required. The fascia iliaca compartment block may also represent a better alternative than the 3-in-1 block because of improved efficacy and efficiency (quicker performance time, lower cost). For blockade of the sciatic nerve, the classic transgluteal approach constitutes a reliable method. Due to a potentially shorter time for sciatic nerve electrolocation and catheter placement than for the transgluteal approach, the subgluteal approach should also be considered. Compared to electrolocation of the peroneal nerve, electrostimulation of the tibial nerve may offer a higher success rate especially with the transgluteal and lateral popliteal approaches. Furthermore, when performing sciatic and femoral blocks with low volumes of local anesthetics, a multiple-injection technique should be used. CONCLUSIONS: Published reports of RCTs provide evidence to formulate limited recommendations regarding optimal approaches and techniques for lower limb anesthesia. Further well-designed and meticulously executed RCTs are warranted, particularly in light of new techniques involving ultrasonographic guidance.     

Continuous shoulder analgesia via an indwelling axillary brachial plexus catheter

Continuous interscalene brachial plexus blockade can provide anesthesia and analgesia in the shoulder region. Difficulty accessing the interscalene space and premature displacement of interscalene catheters may preclude their use in certain situations. We present two case reports in which a catheter was advanced from the axilla along the brachial plexus sheath to the interscalene space to provide continuous cervicobrachial plexus analgesia. In the first case report, previous neck surgery made the anatomic landmarks for performing an interscalene block very difficult. An epidural catheter was advanced from the axillary brachial plexus sheath to the interscalene space under fluoroscopic guidance. This technique provided both intraoperative analgesia for shoulder surgery as well as 24-hour postoperative analgesia by an infusion of 0.125% bupivacaine. In the second case report, a catheter was inserted in a similar fashion from the axillary to the interscalene space to provide 14 days of continuous analgesia in the management of complex regional pain syndrome. We have found that this technique allows us to secure the catheter more easily than with the traditional interscalene approach and thus prevents premature dislodgment. This approach may be a suitable alternative when either an interscalene or an infraclavicular catheter may not be inserted.     

Block of the brachial plexus branches by the humeral route. A prospective study in 503 ambulatory patients. Proposal of a nerve-blocking sequence

BACKGROUND: Brachial plexus is usually approached by the supraclavicular or axillary route. A technique for selective blockade of the branches of the plexus at the humeral canal using electrolocation has recently been proposed. The aim of the present study was to assess the feasibility of this technique in the ambulatory patient and to determine the optimal sequence of nerve-blocking. METHODS: The nerves originating from the brachial plexus were located in the humeral canal, at the junction of the proximal and the middle third of the arm, with a stimulator and blocked using either lidocaine or a mixture of lidocaine and bupivacaine, depending on the anticipated duration of surgery. The minimal stimulating intensity eliciting an adequate response, type of local anaesthetic and injected volume, and time of onset of surgical anaesthesia were collected. RESULTS: The study included 503 consecutive ambulatory patients due to undergo surgery of the elbow, wrist or hand in one year. Suitable anaesthesia was obtained with the humeral blockade in 82.1% of cases. In the remaining 17.9%, an additional block at the elbow was required, mainly for ulnar and median nerves. The onset times of sensory blocks were the longest for the median nerve, similar for the radial and ulnar nerves, shorter for the musculocutaneous nerve and the shortest for the medial brachial and antebrachial cutaneous nerves. The difference was more significant with the lidocaine-bupivacaine mixture, than with lidocaine alone (P<0.001 vs P<0.05, respectively). The onset times of motor blocks were the longest for the median nerve (P<0.05) and the shortest for the musculocutaneous nerve (P<0.001). Neither nervous nor vascular complications occurred. CONCLUSION: This study shows that the nerve block at the humeral canal is an efficient and safe technique. Considering the onset times of nerve blocks, the following sequence for blockade can be recommended: median, ulnar, radial, musculocutaneous, medial (brachial and antebrachial) cutaneous nerves. The selective blockade of the main nerves of the upper limb at the humeral canal can be recommended for surgery of the forearm and the hand in the ambulatory patient.     

Increased body mass index and ASA physical status IV are risk factors for block failure in ambulatory surgery — an analysis of 9,342 blocks

PURPOSE: Regional anesthesia can be the technique of choice for selected ambulatory surgery procedures, but in spite of its benefits, it has an inherent failure rate even in experienced hands. We examine the efficacy and factors associated with failure of ambulatory regional anesthesia techniques. METHODS: This study included 9,342 blocks performed on 7,160 patients at the Duke University Ambulatory Surgery Center. Blocks were classified as interscalene, supraclavicular, axillary, lumbar plexus, femoral, sciatic, ankle, paravertebral, spinal, and other (frequency less than 100). A block was considered surgical if a single attempt at placing the block resulted in a complete sensory, motor, and sympathetic nerve block. Multiple logistic regression analyses were used to assess the risk-adjusted association between patient characteristics and block failure. RESULTS: Paravertebral blocks and those considered in the "other" category had significantly higher failure rates (P < 0.001), while spinal and lumbar plexus blocks had lower than average rates of failure (P < 0.001 and P = 0.03, respectively).In multiple logistic regression analyses excluding paravertebral blocks, body mass index (BMI) scores greater than 25 (P values: BMI 25-29: < 0.001; BMI 30-34: P < 0.001; BMI 35: P < 0.001) and ASA physical status IV (P < 0.001) were significantly associated with higher block failure rates. CONCLUSION: High BMI and ASA IV are independent risk factors for block failure in ambulatory surgery patients.     

Brachial plexus. Anesthesia and analgesia

This review explains the different approaches to the brachial plexus (posterior cervical, interscalene, supra- and infraclavicular, and axillary) and their advantages and disadvantages (indications, contraindications, and complications) for surgery and postoperative or chronic pain management. One of the focussed areas of this review is the use of continuous catheter techniques. Information about the most commonly used local anesthetics as well as adjuncts suggested in the literature is summarized. As essential components for the success of those techniques, organizational and documentation requirements are described. In summary, regional techniques for single shot or continuous block of the brachial plexus are an efficient and safe way of providing anesthesia and analgesia for surgery or pain in the region of the shoulder, arm, or hand.     

Plexus brachialis

This review explains the different approaches to the brachial plexus (posterior cervical, interscalene, supra- and infraclavicular, and axillary) and their advantages and disadvantages (indications, contraindications, and complications) for surgery and postoperative or chronic pain management. One of the focussed areas of this review is the use of continuous catheter techniques. Information about the most commonly used local anesthetics as well as adjuncts suggested in the literature is summarized. As essential components for the success of those techniques, organizational and documentation requirements are described. In summary, regional techniques for single shot or continuous block of the brachial plexus are an efficient and safe way of providing anesthesia and analgesia for surgery or pain in the region of the shoulder, arm, or hand.     

Ultrasound-guided supraclavicular vs infraclavicular brachial plexus blocks in children

Background: Supraclavicular brachial plexus blocks are not common in children because of risk of pneumothorax. However, infraclavicular brachial plexus blocks have been described in paediatric patients both with nerve stimulation and ultrasound (US)‐guidance. US‐guidance reduces the risk of complications in supraclavicular brachial plexus blocks in adults. Objective: To compare the success rate, complications and time of performance of US‐guided supraclavicular vs infraclavicular brachial plexus blocks in children. Material and methods: Eighty children, 5–15 years old, scheduled for upper limb surgery were divided into two randomized groups: group S (supraclavicular), n = 40, and group I (infraclavicular), n = 40. All blocks performed were exclusively US‐guided, by a senior anaesthesiologist with at least 6 months of experience in US‐guided blocks. For supraclavicular blocks the probe was placed in coronal‐oblique‐plane in the supraclavicular fossa and the puncture was in‐plane (IP) from lateral to medial. For infraclavicular blocks the probe was placed parallel and below the clavicle and the puncture was out‐of‐plane. Ropivacaine 0.5% was administered up to a maximum of 0.5 ml·kg^?1 until appropriate US‐guided‐spread was achieved. Block duration and volumes of ropivacaine used (mean±1SD) in the supraclavicular approach were recorded. Success rate (mean ± 1 SD, 95%confidence interval), complications rate and time to perform the block (two‐tailed Student′s test) were recorded both for supraclavicular and infraclavicular approaches. Results: In the US‐guided supraclavicular brachial plexus blocks, the duration of the sensory block was 6.5 ± 2 h and of the motor block was 4 ± 1 h. The volume of ropivacaine used in this group was 6 ± 2 ml. In group I, 88% of blocks achieved surgical anaesthesia without any supplemental analgesia compared with 95% in group S (P = 0.39; difference=7%; 95% CI: ?10% to 24%). Failures in group I were because of arterial puncture and insufficient ulnar or radial sensory block. Failures in group S were because of insufficient ulnar sensory block. No pneumothorax or Horner’s syndrome was recorded in either group. The mean time (SD) to perform the block was in group I: 13 min (range 5–16) and in group S: 9 min (range 7–12); the 95% CI for this difference was 2–6 min and was statistically significant (P < 0.05). Conclusions: (i) Ultrasound‐guided supraclavicular and infraclavicular brachial plexus blocks are effective in children. (ii) There has been no pneumothorax in 40 US‐guided supraclavicular brachial plexus blocks performed by anaesthesiologists already trained in US‐guided regional anaesthesia using an IP technique in children ≥5 years old. (iii) In this study, the supraclavicular approach of the brachial plexus was faster to perform than the infraclavicular one.     

Comparison of two different techniques for brachial plexus block: infraclavicular versus axillary technique

BACKGROUND: Brachial plexus block via the axillary approach is problematic in patients with limited arm mobility. In such cases, the infraclavicular approach may be a valuable alternative. The purpose of our study was to compare axillary and infraclavicular techniques for brachial plexus block in patients undergoing arm or forearm surgery. METHODS: After institutional approval and informed consent were obtained, 30 patients (ASA physical status I or II) scheduled for forearm and hand surgery under brachial plexus anesthesia were included in the study. Patients were randomly allocated into two groups. Brachial plexus block was performed via the axillary approach in the Group A patients and via the infraclavicular approach in the Group I patients using a peripheral nerve stimulator. All blocks were performed with a total dose of 40 ml 0.375% bupivacaine. RESULTS: In each nerve territory (radial, ulnar, median, and musculocutaneous), the mean values of the degree and the duration of the sensory block and motor block were not significantly different between the two groups (P > 0.05). Inadvertent vessel puncture was significantly more frequent in the axillary approach (P < 0.05). CONCLUSION: Brachial plexus block performed via the infraclavicular approach is as safe and effective as the axillary approach. Infraclavicular approach may be preferred to the axillary approach when the upper arm mobility is impaired or not desired.     

Repair of isolated axillary nerve lesions after infraclavicular brachial plexus injuries: case reports

Stretch injuries of the infraclavicular brachial plexus have a much better prognosis for spontaneous recovery than do their supraclavicular counterparts. We present three patients with stretch injuries of the infraclavicular brachial plexus who had spontaneous restoration of function in all muscles except the deltoid. Decreased shoulder abduction was a serious handicap to these individuals. At surgical exploration, each patient had an isolated, complete axillary nerve disruption at the quadrilateral space. Deltoid muscle function was restored in all three patients by repair of the axillary nerve with sural nerve grafts across the quadrilateral space.