High-resolution ultrasonography for the diagnosis of brachial plexus root lesions

Ultrasound accuracy for brachial plexus pathology

AIM

To determine (a) the accuracy of ultrasound in detecting brachial plexus pathology and (b) outline the advantages and limitations of ultrasound compared to MRI for imaging the brachial plexus.

MATERIAL AND METHODS

cases with clinically suspected brachial plexus pathology were evaluated first by ultrasound, followed by MRI. Patients with prior brachial plexus imaging were excluded. The final diagnosis was based on a combination of ultrasound, MRI, clinical follow-up, and surgical findings. The accuracy of the ultrasound was assessed by comparing the ultrasound and the final diagnoses. The mean clinical follow-up time following ultrasound was 1.8 ± 1.4 years.

RESULTS

Ninety-two (64%) of the 143 cases had normal brachial plexus ultrasound and MRI examinations. Fifty-one (36%) of 143 cases had brachial plexus pathology on MRI, comprising post-radiation fibrosis (n=25, 49%), nerve sheath tumor (n=11, 21%), traumatic injury (n=7, 14%), inflammatory polyneuropathy (n=4, 8%), malignant infiltration (n=2, 4%), desmoid fibromatosis (n=1,2%), and neuralgic amyotrophy (n=1, 2%). Overall diagnostic accuracy of ultrasound for brachial plexus pathology was 98% (140/143), with three discordant cases (neuralgic amyotrophy n=1, inflammatory neuropathy n=1, postradiation fibrosis n=1) regarded as normal on ultrasound assessment. Sensitivity, specificity, and positive and negative predictive value of ultrasound for identifying brachial plexus pathology were 94%, 100%, 100%, and 97%, respectively.

CONCLUSION

Ultrasound identifies brachial plexus pathology with high accuracy and specificity, showing comparable diagnostic efficacy to MRI. Ultrasound can serve as an effective first-line imaging investigation for suspected brachial plexus pathology.

Hydrodissection of the Eighth Cervical Nerve Root for Scapular Girdle Pain Associated With Nonunion of the First Rib Stress Fracture: A Case Report

The first rib stress fracture is a rare overuse injury, with nonunion posing challenges to athletic performance. We report an 18-year-old international-level gymnast diagnosed with the nonunion of the first rib stress fracture, experiencing pain extending to the medial scapular area. Traditional treatments provided no relief, with tests suggesting C8 nerve root involvement. This study introduces a novel approach targeting the C8 nerve root using hydrodissection, which alleviates the pain. Post-procedure, the patient resumed competition without recurrence of pain after a year. This case suggests that pain due to first rib stress fracture nonunion might be associated with the C8 nerve root, and hydrodissection could be a potentially effective treatment.

Diagnosis of thoracic outlet syndrome with the lower trunk compression of brachial plexus by high-frequency ultrasonography

BACKGROUND

Thoracic outlet syndrome (TOS) with the lower trunk compression of brachial plexus (BP) is difficult to diagnosis. This study aimed to summarize the features of thoracic outlet syndrome (TOS) with the lower trunk compression of brachial plexus observed on high-frequency ultrasonography (HFUS).

METHODS

The ultrasound data of 27 patients who had TOS with the lower trunk compression of brachial plexus were collected and eventually confirmed by surgery. The imaging data were compared, and the pathogenesis of TOS was analyzed on the basis of surgical data.

RESULTS

TOS occurred predominantly in females (70.4%). Most cases had unilateral involvement (92.6%), mainly on the right side (66.7%). The HFUS features of TOS can be summarized as follows: (1) Lower trunk compression. HFUS revealed focal thinning that reflected compression at the level of the lower trunk; furthermore, the distal part of the nerve was thickened for edema (Affected side: 0.49 ± 0.12 cm vs. Healthy side: 0.38 ± 0.06, P = 0.009), and the cross-sectional area of brachial plexus cords was markedly greater on the injured side than on the healthy side (0.95 ± 0.08 cm² vs. 0.65 ± 0.11 cm², P = 0.004). (2) Hyperechoic fibromuscular bands behind the compressed nerve (mostly the scalenus minimus muscle). (3) Abnormal bony structures: cervical ribs or elongated transverse processes of the 7th cervical vertebra (C7). Surgical results showed that the etiological factors contributing to TOS were (1) muscle hypertrophy and/or fibrosis (100%) and (2) cervical ribs/elongated C7 transverse processes (20.7%).

CONCLUSION

TOS with the lower trunk compression of brachial plexus can be diagnosed accurately and reliably by high-frequency ultrasound.

Diagnostic performance of preoperative ultrasound for traumatic brachial plexus root injury: A comparison study with an electrophysiology study

Purpose

Accurate preoperative assessment for traumatic brachial plexus injury (BPI) is critical for clinicians to establish a treatment plan. The objective of this study was to investigate the diagnostic performance of preoperative ultrasound (US) through comparison with an electrophysiology study (EPS) in the assessment of traumatic brachial plexus (BP) root injury.

Materials and methods

We performed a retrospective study in patients with traumatic BPI who had preoperative US and EPS, excluding obstetric palsy and other nontraumatic neuropathies. US examination was performed on an EPIQ 5 color Doppler equipment. EPS was performed on a Keypoint 9033A07 Electromyograph/Evoked Potentials Equipment, testing electromyography (EMG), nerve conduction studies (NCS), and somatosensory evoked potentials (SEP). Each BP root of all patients was assessed by US and EPS as completely injured or incompletely injured, respectively. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated based on the correlation with intraoperative findings. The accuracy of US and EPS were compared using the McNemar test. The added benefit of US was evaluated by comparing the sensitivity and specificity between the combined tests with EPS using the McNemar test.

Results

This study included 49 patients with traumatic BPI who underwent BP surgeries from October 2018 to September 2022. Surgical exploration confirmed 89 completely injured BP roots in 28 patients. US correctly detected 80 completely injured BP roots (sensitivity, 0.899; specificity, 0.981; PPV, 0.964; NPV, 0.944; accuracy, 0.951). EPS correctly detected 75 completely injured BP roots (sensitivity, 0.843; specificity, 0.929; PPV, 0.872; NPV, 0.912; accuracy, 0.898). US showed significantly higher accuracy than EPS (p = 0.03). When combining US and EPS for completely injured BP root detection, the sensitivity of the inclusive combination (0.966) was significantly higher than EPS alone (p = 0.000977), and the specificity of the exclusive combination (1.000) was significantly higher than EPS alone (p = 0.000977).

Conclusion

Preoperative US is an effective diagnostic tool in the assessment of traumatic BP root injury. US had higher accuracy than EPS in this study. Sensitivity and specificity were significantly higher than EPS when US was combined with EPS.

Rare malignant melanotic nerve sheath tumors of the upper limb nerves: utility of high-frequency ultrasonography in preoperative imaging

Melanotic nerve sheath tumor (MNST) is a rare variant of schwannoma. Here, we report an unusual case of multiple MNST lesions located in the upper limb nerves. The patient presented with a mass on the left wrist in 2016 and another mass on the left thumb in 2017. In both instances, magnetic resonance imaging scans confirmed multiple giant-cell tumors of the tendon sheath. Persistent pain in the left upper limb and numbness in the ring finger and little finger recurred in 2021. High-frequency ultrasound (HFUS) showed that the left brachial plexus nerves (C5-8) were widened compared with those on the contralateral side; the neuroma formed at the lateral cord, and the median nerve was markedly thickened. The surgical findings were consistent with the ultrasound results. Pathology confirmed that the tumors were malignant MNSTs. HFUS is important for preoperative diagnosis and lesion localization, even identifying some lesions that are unrecognized on magnetic resonance imaging; thus, HFUS is crucial for improving surgical strategy and decision-making.

Diagnostic Ability of Ultrasonography in Brachial Plexus Root Injury at Different Stages Post-trauma

Brachial plexus (BP) root injury often results in disability of the upper extremities. Improvements in high-frequency ultrasonography have enabled the visualization of BP nerve roots. This study was aimed at quantifying the diagnostic accuracy of ultrasonography in BP root injury at different stages post-trauma. A consecutive series of 170 patients with BP root injury between 2015 and 2019 were studied retrospectively and divided into three groups on the basis of time between injury and ultrasound examination (≤1 mo, 1-3 mo, >3 mo). Diagnosis of complete BP root injury under ultrasound was determined using a pre-defined criterion, including pseudomeningocele, retraction and rupture. Diagnostic accuracy was calculated based on surgical findings and intra-operative electrophysiological tests. Rates of detection of the cervical (C5-C8) and thoracic (T1) nerve roots under ultrasound were 99.4%, 99.4%, 99.4%, 95.9% and 79.4%, respectively. The sensitivity for complete BP root injury was 0.74, and the specificity was 0.91. No significant differences in sensitivity or specificity were observed across time stages. Ultrasound exhibited substantial consistency with surgical findings (κ = 0.70) for complete BP root injury at any stage post-injury. Ultrasound can be an optional method of diagnosis of complete BP root injury at an early stage post-injury.

ACR Appropriateness Criteria® Plexopathy: 2021 Update

Plexopathy may be caused by diverse pathologies, including trauma, nerve entrapment, neoplasm, inflammation, infection, autoimmune disease, hereditary disease, and idiopathic etiologies. For patients presenting with brachial or lumbosacral plexopathy, dedicated plexus MRI is the most appropriate initial imaging modality for all clinical scenarios and can identify processes both intrinsic and extrinsic to the nerves. Other imaging tests may be appropriate for initial imaging depending on the clinical scenario. This document addresses initial imaging strategies for brachial and lumbosacral plexopathy in the following clinical situations: nontraumatic plexopathy with no known malignancy, traumatic plexopathy (not perinatal), and plexopathy occurring in the context of a known malignancy or posttreatment syndrome. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Diffusion tensor imaging of the roots of the brachial plexus: a systematic review and meta-analysis of normative values

Purpose

Diffusion tensor magnetic resonance imaging (DTI) characterises tissue microstructure and provides proxy measures of myelination, axon diameter, fibre density and organisation. This may be valuable in the assessment of the roots of the brachial plexus in health and disease. Therefore, there is a need to define the normal DTI values.

Methods

The literature was systematically searched for studies of asymptomatic adults who underwent DTI of the brachial plexus. Participant characteristics, scanning protocols, and measurements of the fractional anisotropy (FA) and mean diffusivity (MD) of each spinal root were extracted by two independent review authors. Generalised linear modelling was used to estimate the effect of experimental conditions on the FA and MD. Meta-analysis of root-level estimates was performed using Cohen's method with random effects.

Results

Nine articles, describing 316 adults (1:1 male:female) of mean age 35 years (SD 6) were included. Increments of ten diffusion sensitising gradient directions reduced the mean FA by 0.01 (95% CI 0.01, 0.03). Each year of life reduced the mean MD by 0.03 × 10^-3 mm²/s (95% CI 0.01, 0.04). At 3-T, the pooled mean FA of the roots was 0.36 (95% CI 0.34, 0.38; I ² 98%). The pooled mean MD of the roots was 1.51 × 10^-3 mm²/s (95% CI 1.45, 1.56; I ² 99%).

Conclusions

The FA and MD of the roots of the brachial plexus vary according to experimental conditions and participant factors. We provide summary estimates of the normative values in different conditions which may be valuable to researchers and clinicians alike.

High definition ultrasound imaging of the individual elements of the brachial plexus above the clavicle

Background and objectives

Ultrasonography of the brachial plexus (BP) has been described but there are limited data on visualization of the T1 ventral ramus and the inferior trunk. This prospective observational study aimed to evaluate a high definition ultrasound imaging technique to systematically identify the individual elements of the BP above the clavicle.

Methods

Five healthy young volunteers underwent high definition ultrasound imaging of the BP above the clavicle. The ultrasound scan sequence (transverse oblique scan) commenced at the supraclavicular fossa after which the transducer was slowly swept cranially to the upper part of the interscalene groove and then in the reverse direction to the supraclavicular fossa. The unique sonomorphology of the C7 transverse process was used as the key anatomic landmark to identify the individual elements of the BP in the recorded sonograms.

Results

The neural elements of the BP that were identified in all volunteers included the ventral rami of C5–T1, the three trunks, divisions of the superior trunk, and formation of the inferior trunk (C8–T1). The C6 ventral ramus exhibited echogenic internal septation with a split (bifid) appearance in four of the five volunteers. In three of the four volunteers with a bifid C6 ventral ramus, the C7 ventral ramus was also bifid.

Conclusion

We have demonstrated that it is feasible to accurately identify majority of the main components of the BP above the clavicle, including the T1 ventral ramus and the formation of the inferior trunk, using high definition ultrasound imaging.

Trial registration number

ChiCTR1900021749.

Ultrasound imaging of brachial plexus trauma in gunshot injury

INTRODUCTION

Brachial plexus trauma related to gunshot (GS) injury requires early examination and characterization to ensure appropriate treatment. Magnetic resonance imaging (MRI) may be contraindicated when there are metal fragments in a patient's body. Ultrasound (US) may present an alternative to imaging GS-related brachial plexus injury.

METHODS

Three patients with GS-related brachial plexus injury who underwent US imaging evaluation at our institution were identified. A retrospective review of the patients' medical records was performed.

RESULTS

US characterization of nerve abnormalities after GS injury to the brachial plexus was in agreement with electrodiagnostic and intraoperative findings.

DISCUSSION

Information from the US reports was useful in preparation for brachial plexus reconstruction surgery. As such, US has unique utility when MRI cannot be performed. US imaging can provide useful characterization of the brachial plexus after GS injury when performed by an experienced operator. Muscle Nerve 59:707-711, 2019.

Shear Wave and Strain Elastographic Features of the Brachial Plexus in Healthy Adults: Reliability of the Findings-a Pilot Study

OBJECTIVES

To determine the sonoelastographic findings for the normal brachial plexus via shear wave elastography (SWE) and strain elastography (SE) and the reliability of the measurements.

METHODS

Thirty-nine healthy adult volunteers were included in the study. The brachial plexus was evaluated with SWE and SE at the interscalene region by 2 observers separately, and the observers were unaware of each other's outcomes. The elastic modulus (kilopascals), shear wave velocity (SWV, meters per second), and strain ratio were obtained. Elasticity patterns on SE were assessed as hard, intermediate, and soft. An intraclass correlation coefficient analysis was performed for determining the reliability of sonoelastographic findings. The correlation of sonoelastographic features with age and sex was investigated.

RESULTS

The volunteers included 13 men and 26 women. The mean age of the participants ± SD was 36.2 ± 7.8 (range, 25-56) years. The mean elasticity modulus values of the brachial plexus for observers 1 and 2 were 17.03 (95% confidence interval [CI], 15.03, 19.03) and 13.83 (95% CI, 12.23, 15.43) kPa, respectively; the SWVs were 2.24 (95% CI, 2.12, 2.36) and 2.04 (95% CI, 1.93, 2.15) m/s; and the strain ratios were 1.20 (95% CI, 1.18, 1.25) 1.38 (95% CI, 1.22, 1.54). The elasticity pattern was mostly intermediate stiffness for both observers (n = 72 [92.3%]; n = 75 [96.1%]). The intraclass correlation coefficient was poor to moderate and statistically significant for the elastic modulus, SWV, and elasticity pattern (P < .05 for all parameters). The sonoelastographic characteristics of the brachial plexus had no correlation with age or sex.

CONCLUSIONS

The reliability and reproducibility of sonoelastography of the brachial plexus are low, and the appropriateness of this technique in this manner is controversial.

Magnetic resonance imaging for detecting root avulsions in traumatic adult brachial plexus injuries: protocol for a systematic review of diagnostic accuracy

BACKGROUND

Adult brachial plexus injuries (BPI) are becoming more common. The reconstruction and prognosis of pre-ganglionic injuries (root avulsions) are different to other types of BPI injury. Preoperative magnetic resonance imaging (MRI) is being used to identify root avulsions, but the evidence from studies of its diagnostic accuracy are conflicting. Therefore, a systematic review is needed to address uncertainty about the accuracy of MRI and to guide future research.

METHODS

We will conduct a systematic search of electronic databases alongside reference tracking. We will include studies of adults with traumatic BPI which report the accuracy of preoperative MRI (index test) against surgical exploration of the roots of the brachial plexus (reference standard) for detecting either of the two target conditions (any root avulsion or any pseudomeningocoele as a surrogate marker of root avulsion). We will exclude case reports, articles considering bilateral injuries and studies where the number of true positives, false positives, false negatives and true negatives cannot be derived. The methodological quality of the included studies will be assessed using a tailored version of the QUADAS-2 tool. Where possible, a bivariate model will be used for meta-analysis to obtain summary sensitivities and specificities for both target conditions. We will investigate heterogeneity in the performance of MRI according to field strength and the risk of bias if data permits.

DISCUSSION

This review will summarise the current diagnostic accuracy of MRI for adult BPI, identify shortcomings and gaps in the literature and so help to guide future research.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016049702 .

[Diagnostic nerve ultrasonography]

CLINICAL/METHODICAL ISSUE

For the diagnostics of nerve lesions an imaging method is necessary to visualize peripheral nerves and their surrounding structures for an etiological classification.

STANDARD RADIOLOGICAL METHODS

Clinical neurological and electrophysiological investigations provide functional information about nerve lesions. The information provided by a standard magnetic resonance imaging (MRI) examination is inadequate for peripheral nerve diagnostics; however, MRI neurography is suitable but on the other hand a resource and time-consuming method.

METHODICAL INNOVATIONS

Using ultrasonography for peripheral nerve diagnostics.

PERFORMANCE

With ultrasonography reliable diagnostics of entrapment neuropathies and traumatic nerve lesions are possible. The use of ultrasonography for neuropathies shows that a differentiation between different forms is possible.

ACHIEVEMENTS

Nerve ultrasonography is an established diagnostic tool. In addition to the clinical examination and clinical electrophysiology, structural information can be obtained, which results in a clear improvement in the diagnostics. Ultrasonography has become an integral part of the diagnostic work-up of peripheral nerve lesions in neurophysiological departments.

PRACTICAL RECOMMENDATIONS

Nerve ultrasonography is recommended for the diagnostic work-up of peripheral nerve lesions in addition to clinical and electrophysiological investigations. It should be used in the clinical work-up of entrapment neuropathies, traumatic nerve lesions and spacy-occupying lesions of nerves.

The diagnostic accuracy of 1.5T magnetic resonance imaging for detecting root avulsions in traumatic adult brachial plexus injuries

Identification of root avulsions is of critical importance in traumatic brachial plexus injuries because it alters the reconstruction and prognosis. Pre-operative magnetic resonance imaging is gaining popularity, but there is limited and conflicting data on its diagnostic accuracy for root avulsion. This cohort study describes consecutive patients requiring brachial plexus exploration following trauma between 2008 and 2016. The index test was magnetic resonance imaging at 1.5 Tesla and the reference test was operative exploration of the supraclavicular plexus. Complete data from 29 males was available. The diagnostic accuracy of magnetic resonance imaging for root avulsion(s) of C5-T1 was 79%. The diagnostic accuracy of a pseudomeningocoele as a surrogate marker of root avulsion(s) of C5-T1 was 68%. We conclude that pseudomeningocoles were not a reliable sign of root avulsion and magnetic resonance imaging has modest diagnostic accuracy for root avulsions in the context of adult traumatic brachial plexus injuries.

LEVEL OF EVIDENCE

III.

Microanatomy of the brachial plexus roots and its clinical significance

PURPOSE

To provide the anatomical basis of brachial plexus roots for the diagnosis and treatment of brachial plexus root avulsion injury.

METHODS

The morphological features of brachial plexus roots were observed and measured on 15 cervicothoracic spine of adult cadavers. The relationship of brachial plexus nerve roots and the surrounding tissues also were observed, as well as the blood supply of anterior and posterior roots of the brachial plexus.

RESULTS

Origination of the nerve roots in the dorsal-ventral direction from the midline was fine-tuned at each level along the spinal cord. The minimum distance of the origin of the nerve root to midline was 2.2 mm at C ₅, while the maximum was 3.1 mm at T ₁. Inversely, the distance between the origin of the posterior root and the midline of the spinal cord gradually decreased, the maximum being 4.2 mm at C ₅ and minimum 2.7 mm at T ₁. Meanwhile, there was complicated fibrous connection among posterior roots of the brachial plexus. The C _5-6 nerve roots interlaced with tendons of the scalenus anterior and scalenus medius and fused with the transverse-radicular ligaments in the intervertebral foramina. However, these ligaments were not seen in C _7-8, and T ₁. The blood supply of the anterior and posterior roots of the brachial plexus was from the segmental branches of the vertebral artery, deep cervical artery and ascending cervical artery, with a mean outer diameter of 0.61 mm.

CONCLUSIONS

The systematic and comprehensive anatomic data of the brachial plexus roots provides the anatomical basis to diagnose and treat the brachial plexus root avulsion injury.

Advances in the neurological and neurosurgical management of peripheral nerve trauma

Peripheral nerve trauma frequently affects younger people and may result in significant and long-lasting functional disability. Currently, diagnosis and monitoring of peripheral nerve injury relies on clinical and electrodiagnostic information, supplemented by intraoperative electrophysiological studies. However, in a significant proportion of nerve injuries, the likelihood of spontaneous regeneration resulting in good functional outcome remains uncertain and unnecessary delays to treatment may be faced while monitoring for recovery. Advances in non-invasive imaging techniques to diagnose and monitor nerve injury and regeneration are being developed, and have the potential to streamline the decision-making process. In addition, advances in operative and non-operative treatment strategies may provide more effective ways to maximise functional outcomes following severe peripheral nerve trauma. This review discusses these advances in light of the current state of the art of management of peripheral nerve trauma.