Incidence of intraneural needle insertion in ultrasound-guided femoral nerve block: a comparison between the out-of-plane versus the in-plane approaches

The role of high-resolution ultrasound and MRI in the evaluation of peripheral nerves in the lower extremity

Lower extremity peripheral neuropathy is a commonly encountered neurologic disorder, which can lead to chronic pain, functional disability, and decreased quality of life for a patient. As diagnostic imaging modalities have improved, imaging has started to play an integral role in the detection and characterization of peripheral nerve abnormalities by non-invasively and accurately identifying abnormal nerves as well as potential causes of neuropathy, which ultimately leads to precise and timely treatment. Ultrasound, which has high spatial resolution and can quickly and comfortably characterize peripheral nerves in real time along with associated denervation muscle atrophy, and magnetic resonance neurography, which provides excellent contrast resolution between nerves and other tissues and between pathologic and normal segments of peripheral nerves, in addition to assessing reversible and irreversible muscle denervation changes, are the two mainstay imaging modalities used in peripheral nerve assessment. These two modalities are complimentary, and one may be more useful than the other depending on the nerve and location of pathology. Imaging must be interpreted in the context of available clinical information and other diagnostic studies, such as electrodiagnostic tests. Here, we offer a comprehensive overview of the role of high-resolution ultrasound and magnetic resonance neurography in the evaluation of the peripheral nerves of the lower extremity and their associated neuropathies.

The practice of regional anesthesia in Belgium – a national survey

Background : National surveys are useful to assess the state of regional anaesthesia (RA) practice in a particular country. Given that such information was lacking in Belgium, we conducted a survey to evaluate the Belgian practice of peripheral nerve blocks (PNBs) with a particular focus on its safety aspects. Methods : A survey was sent by email to 1510 Belgian anesthesiologists. No identifying information was collected. Data were collected between September 2019 and October 2019. Results : We collected 324 questionnaires (response rate 21%). Eighty five percent of respondents perform regularly PNB. 99% place a venous access before performing a block, and more than 90% monitor patients with minimum peripheral pulse oximetry. The majority monitor patients for a minimum of 30 minutes after the injection of local anesthetic (LA). Ultrasound-guided technique for RA is used by 89% of respondents. Neurostimulation is totally abandoned by 20% of them. Monitoring of injection pressures is performed by 21% of respondents. More than 50% of respondents use sterile gloves, surgical drapes and a mask. With regards to the solution of LA used, 52% of respondents never mix LAs. An adjuvant is always used by 15% of the respondents while 10% of them never use them. Conclusions : This survey suggests that the practice of PNBs in Belgium is in line with the current international guidelines. This survey can serve as a benchmark for future evaluation and comparison between RA techniques. These observations should be taken into account for the implementation of national guidelines and therefore for the improvement of safety in the practice of PNBs.

Ulnar Neuropathy at the Elbow: From Ultrasound Scanning to Treatment

Ulnar neuropathy at the elbow (UNE) is commonly encountered in clinical practice. It results from either static or dynamic compression of the ulnar nerve. While the retroepicondylar groove and its surrounding structures are quite superficial, the use of ultrasound (US) imaging is associated with the following advantages: (1) an excellent spatial resolution allows a detailed morphological assessment of the ulnar nerve and adjacent structures, (2) dynamic imaging represents the gold standard for assessing the ulnar nerve stability in the retroepicondylar groove during flexion/extension, and (3) US guidance bears the capability of increasing the accuracy and safety of injections. This review aims to illustrate the ulnar nerve's detailed anatomy at the elbow using cadaveric images to understand better both static and dynamic imaging of the ulnar nerve around the elbow. Pathologies covering ulnar nerve instability, idiopathic cubital tunnel syndrome, space-occupying lesions (e.g., ganglion, heterotopic ossification, aberrant veins, and anconeus epitrochlearis muscle) are presented. Additionally, the authors also exemplify the scientific evidence from the literature supporting the proposition that US guidance is beneficial in injection therapy of UNE. The non-surgical management description covers activity modifications, splinting, neuromobilization/gliding exercise, and physical agents. In the operative treatment description, an emphasis is put on two commonly used approaches-in situ decompression and anterior transpositions.

Ultrasonographic needle tip tracking for in-plane infraclavicular brachialis plexus blocks: a randomized controlled volunteer study

BACKGROUND

Onvision is a new technology for needle tip detection and tracking in ultrasound-guided regional anesthesia. The system consists of a piezoelectric sensor close to the needle tip and an electronic console integrated in the ultrasound system. The needle tip is visualized by a green circle on the ultrasound screen. The aim of the study was to investigate the effect of the new needle tip tracking technology on in-plane infraclavicular plexus blocks.

METHODS

The study was a randomized, controlled, observer blinded cross-over trial in 26 healthy volunteers. Two specialists in anesthesiology performed an ultrasound-guided infraclavicular lateral sagittal brachial plexus block with and without needle tip tracking. Primary outcome was procedure time, measured from insertion of the needle until local anesthesia injection was completed. Secondary outcome measures included the number of hand movements and path lengths (assessed by hand motion analysis), block success rate, onset time and duration, discomfort experienced by the volunteers, and the anesthesiologists' confidence as to whether their block would be successful or not.

RESULTS

Mean (SD) procedure time was 183.0 (56.1) s with and 206.8 (56.2) s without needle tip tracking (p=0.16). There were no significant differences in any of the secondary outcomes. Two volunteers' experienced Horner syndrome after blocks without needle tip tracking. No other adverse events occurred during the study.

CONCLUSION

Our study on needle tip tracking for infraclavicular blocks did not reveal any significant differences between active needle tip tracking and the control procedures, neither for primary outcome nor secondary outcome measurements.

TRIAL REGISTRATION NUMBER

NCT03631914.

Ultrasound-guided sciatic nerve block at the midthigh level in a porcine model: A descriptive study

BACKGROUND AND OBJECTIVE

There are a growing number of porcine models being used for orthopaedic experiments for human beings. Therefore, pain management of those research pigs using ultrasound (US)-guided nerve block can be usefully performed. The aim of this study is to determine optimal US approaches for accessing and localizing the sciatic nerve at the midthigh level, a relevant block site for hindlimb surgery in female Yorkshire pigs.

METHODS

As a first step, we dissected the intubated, blood-washed out pigs (n = 3) and confirmed the anatomical position of the sciatic nerve at midthigh level. After dissection, we found the sciatic nerve, connected with nerve stimulator, and checked the dorsiflexion or plantar flexion of the hindlimb. We matched the sciatic nerve location with the US image. After the pigs were euthanized, the neural structures of the sciatic nerve were confirmed by histological examination with H&E staining. In second step, a main US-guided sciatic nerve block study was done in the intubated, live pigs (n = 8) based on the above study.

RESULTS

In lateral position, the effective US-guided nerve block site was about 6 cm from the patella crease level; immediately proximal to the bifurcation of the sciatic nerve into the tibial nerve and common peroneal nerve. The distal femur was selected as the landmark. There were no vessels or other nerves surrounding the sciatic nerve. The needle-tip was positioned less than 1 cm lateral from the distal femur and about 2 cm deep to skin. 'Donut sign' in US images was confirmed in all 16 nerves.

CONCLUSIONS

Midthigh level sciatic nerve is located superficially, which enables nerve block to be easily performed using US. This is the first study to describe midthigh sciatic nerve block in the lateral position under US guidance in a porcine model from a clinical perspective.

Update on Selective Regional Analgesia for Hip Surgery Patients

In hip surgery, regional anesthesia offers benefits in pain management and recovery. There are a wide range of regional analgesic options; none have shown to be superior. Lumbar plexus block, femoral nerve block, and fascia iliaca block are the most supported by published literature. Other techniques, such as selective obturator and/or lateral femoral cutaneous nerve blocks, represent alternatives. Newer approaches, such as quadratus lumborum block and local infiltration analgesia, require rigorous studies. To realize long-term outcome benefits, postoperative regional analgesia must be tailored to the individual patient and last longer.

Evaluation of a Novel Out-of-Plane Needle Guide

OBJECTIVES

Most ultrasound-guided regional procedures use an in-plane approach. Out-of-plane approaches may be desirable in some situations but can be difficult because of an inability to visualize the needle until it intersects the plane of the ultrasonic beam. Here we present a novel out-of-plane needle guide, using a retreating depth stop, and compare its performance with unguided in-plane and out-of-plane techniques.

METHODS

First- and third-year medical students with no or minimal ultrasound experience were recruited for the study. After a brief training session on in-plane and out-of-plane needling techniques, as well as use of the retreating-stop needle guide, they attempted to place a needle as close as possible to a target embedded in porcine tissue. The total time to complete the procedure was measured. Accuracy was measured by a skilled sonographer, who identified the needle tip and measured the distance to the target. The data were tested for significance using an analysis of variance.

RESULTS

The mean total time spent differed significantly between groups (novel needle guide, 34 seconds; in-plane, 120 seconds; out-of-plane, 113 seconds; P = .021). Needle proximity was on average more accurate with the needle guide, although this difference was not statistically significant (novel needle guide, 8 mm; in-plane, 15 mm; out-of-plane, 14 mm; P = .289).

CONCLUSIONS

In relatively inexperienced sonographers, the retreating-stop needle guide reduced the procedure time compared with in-plane and out-of-plane techniques. No significant changes in needling accuracy were observed.

Low-concentration distal nerve blocks with 0.125% levobupivacaine versus systemic analgesia for ambulatory trapeziectomy performed under axillary block: a randomized controlled trial

BACKGROUND

Trapeziectomy is one of the most painful procedures in ambulatory surgery. This prospective randomized trial aimed to compare postoperative pain control using distal peripheral nerve blocks (dPNB) with a low concentration of a long-acting local anesthetic versus conventional systemic analgesia.

METHODS

Fifty-two patients undergoing trapeziectomy were randomized to receive levobupivacaine 0.125% 5 mL on radial and median nerves at the elbow (dNB group), or not to receive these blocks (control group). In both groups, surgery was performed under axillary block (mepivacaine 1% 20 mL) and the same analgesic regimen was prescribed at discharge. The primary outcome was postoperative pain at 24 and 48 hours after surgery and maximum pain score on the first and second postoperative day. Secondary outcomes were duration of dPNB, rescue analgesia requirements, opioid-related side effects, consumption and effectiveness of antiemetic therapy, and upper limb motor block.

RESULTS

Fifty patients were analyzed. Maximum pain intensity was moderate to severe (dPNB vs. control) in 33.3% vs. 92.3% (P=0.002) on the first day after surgery and 20.8% vs. 80.8% (P<0.001) on the second day. The average duration of analgesia after dPNB was 10 hours and no patient reported motor block. dPNB reduced rescue analgesia requirements and the incidence of postoperative nausea and vomiting (PONV).

CONCLUSIONS

dPNB on target nerves provided better analgesia than systemic analgesia after trapeziectomy performed under axillary block. Opioid consumption and the incidence of PONV were lower in the dPNB group.

Ultrasound-Guided Obturator Nerve Block: A Focused Review on Anatomy and Updated Techniques

This review outlines the anatomy of the obturator nerve and the indications for obturator nerve block (ONB). Ultrasound-guided ONB techniques and unresolved issues regarding these procedures are also discussed. An ONB is performed to prevent thigh adductor jerk during transurethral resection of bladder tumor, provide analgesia for knee surgery, treat hip pain, and improve persistent hip adductor spasticity. Various ultrasound-guided ONB techniques can be used and can be classified according to whether the approach is distal or proximal. In the distal approach, a transducer is placed at the inguinal crease; the anterior and posterior branches of the nerve are then blocked by two injections of local anesthetic directed toward the interfascial planes where each branch lies. The proximal approach comprises a single injection of local anesthetic into the interfascial plane between the pectineus and obturator externus muscles. Several proximal approaches involving different patient and transducer positions are reported. The proximal approach may be superior for reducing the dose of local anesthetic and providing successful blockade of the obturator nerve, including the hip articular branch, when compared with the distal approach. This hypothesis and any differences between the proximal ONB techniques need to be explored in future studies.

A Randomized Double-Blinded Trial on the Effects of Ultrasound Transducer Orientation on Teaching and Learning Ultrasound-Guided Regional Anesthesia

OBJECTIVES

Learning ultrasound-guided regional anesthesia skills, especially needle/ beam alignment, can be especially difficulty for trainees, who can often become frustrated. We hypothesized that teaching novices to orient the transducer and needle perpendicular to their shoulders will improve performance on a standardized task, compared to holding the transducer and needle parallel to the shoulders.

METHODS

This study compared the effects of transducer orientation on trainees' ability to complete a standardized ultrasound-guided nerve block simulation. The time to task completion and percentage of the attempt time without adequate needle visualization were measured. Participants were right-handed healthy adults with no previous ultrasound experience and were randomly assigned to training in either transducer and needle alignment in a coronal plane, parallel to the shoulders (parallel group) or transducer and needle alignment in a sagittal plane, perpendicular to the shoulders (perpendicular group). Participants used ultrasound to direct a needle to 3 targets in a standardized gelatin phantom and repeated this task 3 times. Their efforts were timed and evaluated by an assessor, who was blinded to group assignment.

RESULTS

Data were analyzed on 28 participants. The perpendicular group was able to complete the task more quickly (P < .001) and with a smaller proportion of time lost to inadequate needle visualization (P < .001).

CONCLUSIONS

Ultrasound-guided regional anesthesia trainees complete a standardized task more quickly and efficiently when instructed to hold the transducer and needle in an orientation perpendicular to their shoulders.

Ultrasound-Guided Peripheral Nerve Injection Techniques

OBJECTIVE

Peripheral nerves are well seen using ultrasound (US) imaging, making US an ideal modality for image-guided nerve injections. This article provides a technical guide for common upper and lower extremity peripheral nerve injections, including the median, ulnar, and radial nerves in the upper extremity and the lateral femoral cutaneous, sciatic, common peroneal, tibial, and sural nerves in the lower extremity.

CONCLUSION

US is an effective modality for use in common upper and lower extremity peripheral nerve injections. With correct technique, peripheral nerve injections can be performed safely and are useful for both diagnostic evaluation of and therapy for peripheral neuropathy.

The effect of electromagnetic guidance system on early learning curve of ultrasound for novices

Background

Electromagnetic guidance reveals needle alignment and position relative to the image plane on an ultrasound view. This study compared the early learning curves of novices performing ultrasound-guided needle placement with (n = 10) or without electromagnetic guidance (n = 10).

Methods

Participants performed 30 ultrasound-guided needle placements using an echogenic stick (0.3-cm diameter) as a target inside a phantom model; this early learning period was divided into sequential periods (P1: 1–5, P2: 6–10, P3: 11–15, P4: 16–20, P5: 21–25, P6: 26–30 attempts).

Results

Using an in-plane approach, the time required for needle placement in the EMG group was significantly shorter than that of the non-EMG group in P1, P2, P4, and P6 and the number of needle advances of the EMG group was significantly smaller than that of the non-EMG group in P1 and P2. Using an out-of-plane approaches, the time required for needle placement in the EMG group was significantly shorter than that of the non-EMG group in all periods, but the number of needle advances was similar between both groups in P1–P5.

Conclusions

The electromagnetic guidance system may be beneficial when performing ultrasound guided peripheral nerve blocks or vascular cannulation in the early learning period, especially by inexperienced operators with reducing patient risk.

Use of ultrasound for lower extremity

PURPOSE OF REVIEW

To explore the recent advances in the use of ultrasound for lower extremity blocks, including approaches to the lumbar and sacral plexus blocks.

RECENT FINDINGS

Procedures of the lower extremity often require blocks of the lumbar and sacral plexuses. The use of ultrasound offers some advantages, including the possibility to directly visualize the distribution of local anesthetics.

SUMMARY

Lower extremity blocks under ultrasound guidance often require advanced skills because of the depth of target nerves. This review summarizes the recent advances in the use of ultrasound guidance over traditional techniques.