High-resolution MRI evaluation of neonatal brachial plexus palsy: A promising alternative to traditional CT myelography

Electrodiagnostic studies and new diagnostic modalities for evaluation of peripheral nerve disorders

Electrodiagnostic studies (EDx) are frequently performed in the diagnostic evaluation of peripheral nerve disorders. There is increasing interest in the use of newer, alternative diagnostic modalities, in particular imaging, either to complement or replace established EDx protocols. However, the evidence to support this approach has not been expansively reviewed. In this paper, diagnostic performance data from studies of EDx and other diagnostic modalities in common peripheral nerve disorders have been analyzed and described, with a focus on radiculopathy, plexopathy, compressive neuropathies, and the important neuropathy subtypes of Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), vasculitic neuropathy and diabetic neuropathy. Overall EDx retains its place as a primary diagnostic modality in the evaluated peripheral nerve disorders. Magnetic resonance imaging and ultrasound have developed important complementary diagnostic roles in compressive and traumatic neuropathies and atypical CIDP, but their value is more limited in other neuropathy subtypes. Identification of hourglass constriction in nerves of patients with neuralgic amyotrophy may have therapeutic implications. Investigation of radiculopathy is confounded by poor correlation between clinical features and imaging findings and the lack of a diagnostic gold standard. There is a need to enhance the literature on the utility of these newer diagnostic modalities.

The value of the cinematic volume rendering technique: magnetic resonance imaging in diagnosing tumors associated with the brachial plexus

PURPOSE

To examine the diagnostic advantages and clinical application value of the cinematic volume rendering technique (cVRT) when evaluating the relationship between the brachial plexus, peripheral tumor lesions, and blood vessels.

MATERIALS AND METHODS

Seventy-nine patients with brachial plexus tumors between November 2012 and July 2022 were enrolled in our study. All patients underwent T1WI, T2WI, three-dimensional short recovery time reversal recovery fast spin-echo imaging (3D-STIR-SPACE), and the T1WI enhancement sequence. In addition, cVRT was used to render and obtain a three-dimensional model that clearly showed the location and tissue structure of the brachial plexus nerves and the tumor in all directions.

RESULTS

Seventy-one patients (mean age, 47.1 years; 33 males, 38 females) with tumors around the brachial plexus were included in the study. The brachial plexus nerve, surrounding tumor lesions, and vascular anatomy of all patients were well displayed with cVRT. The tumors of 37 patients manifested as unilateral or bilateral growths along the brachial plexus nerve and were fusiform, spherical, or multiple beaded; seven patients' tumors pushed against the brachial plexus nerve and were circular, lobular, or irregular; sixteen patients' tumors encircled the brachial plexus nerve and were spherical; and eleven patients' tumors infiltrated the brachial plexus nerve and had irregular morphology. The mass has a moderately uniform or uneven signal on T1WI and a high or mixed signal on T2WI. After enhancement, the signal was evenly or unevenly strengthened.

CONCLUSIONS

cVRT clearly showed the origin of tumors associated with the brachial plexus and their relationship with the nerves and peripheral blood vessels, providing reliable information for clinical diagnosis and treatment.

Non-contrast enhancement of brachial plexus magnetic resonance imaging with compressed sensing

PURPOSE

To observe the quality of brachial plexus (BP) images obtained from magnetic resonance imaging (MRI) with 3D T2 STIR SPACE sequence and compressed sensing (CS) and to compare the results with BP images from the same sequence without CS.

METHODS

In this study, compressed sensing was applied to acquire non-contrast BP images from ten healthy volunteers with 3D T2 STIR SPACE sequence to shorten acquisition time without sacrificing image quality. The acquisition time of scanning with CS was compared to that without CS. The quantitative signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated and compared using paired t-test to determine the quality of images with and without CS. The qualitative assessment by three experienced radiologists was performed using a scoring scale from 1 (poor) to 5 (excellent) and analyzed for interobserver agreement on image quality.

RESULTS

The increasing SNR and CNR of images with CS were found in nine regions of BP images (p < 0.001) with faster acquisition time. The result of paired t-test (p < 0.001) illustrates the significant difference between images with CS compared to images without CS. The assessment of observers also shows higher scores for images with CS compared to images without CS.

CONCLUSIONS

This study demonstrates that CS can effectively increase the visibility of images and image boundaries, SNR, and CNR of BP images obtained with 3D T2 STIR SPACE sequence with the good interobserver agreement and within clinically optimal acquisition time compared to images from similar sequence without CS.

A Decade of Imaging Patients with Traumatic Brachial Plexopathy: What have We Learned?

Aim  In this paper, the authors share their experience of imaging patients with traumatic brachial plexopathy by magnetic resonance neurography (MRN) spanning over a period of nearly 10 years. Setting and Design  This was a single-institution, prospective, observational study conducted between August 2012 and March 2022. Materials and Methods  Children and adults presenting to the plastic surgery outpatient department with features of traumatic brachial plexopathy were included in the study. The MRN study was performed in a 1.5T scanner (Magnetom Essenza, Siemens, Erlangen, Germany). The area scanned extended from C3 level to T3 level. Statistical Analysis Descriptive statistics (percentages, mean, median, and mode). Results  A total of 134 patients ( n  = 134) were included in the study. The age of our patients ranged from 6 months to 65 years. The mean age was 24.95 ± 12.10 years, with a median of 23 years. All patients had unilateral injury, and the right side was more commonly involved. Road traffic accident was the most common mode of injury, and blunt crush-avulsion was the most common mechanism of injury. Involvement of shoulder, elbow, and hand together (panplexopathy) was the most common clinical presentation. Conclusion  This study of patients with traumatic brachial plexopathy imaged by MRN, spanning nearly a decade, has led to several interesting observations. The majority of these injuries occur in young men from urban areas who usually present with panplexopathy. The most common mode of injury is road traffic accident, and blunt crush-avulsion is the most common mechanism of injury.

Brachial Plexus Birth Injury: A Review of Neurology Literature Assessing Variability and Current Recommendations

BACKGROUND

Publications regarding the epidemiology and management of brachial plexus birth injury (BPBI) were evaluated to investigate treatment guidelines for children with BPBI.

METHODS

A search of neurology literature from 1990 to 2019 was performed using PubMed, Scopus, and Medline. Data including incidence, risk factors, spontaneous recovery rates, imaging studies, treatment recommendations, and indications and timing for surgery were collected.

RESULTS

A total of 46 total studies were reviewed. Reported incidence rates for BPBI ranged from 0.3 to 3 per 1000 births. Spontaneous recovery rates had an average reported range from 66% to 75%. Physical and occupational therapy were recommended in 37% of articles. Computed tomographic myelogram and magnetic resonance imaging of the brachial plexus were the most commonly recommended imaging studies for BPBI. Timelines for surgical interventions ranged from age three to nine months. Early referral was recommended in 28% of the articles included in the review.

CONCLUSIONS

Given the inconsistencies in spontaneous recovery rates, imaging recommendations, and timing of referral, establishing consistent clinical guidelines for patients with BPBI is crucial for management. Early referral to specialists for evaluation and treatment may improve outcomes in children with BPBI.

Diagnostic accuracy of magnetic resonance imaging for nerve injury in obstetric brachial plexus injury: protocol for systematic review and meta-analysis

BACKGROUND

Early and accurate clinical diagnosis of the extent of obstetric brachial plexus injury (OBPI) is challenging. The current gold standard for delineating the nerve injury is surgical exploration, and synchronous reconstruction is performed if indicated. Magnetic resonance imaging (MRI) is a non-invasive method of assessing the anatomy and severity of nerve injury in OBPI but the diagnostic accuracy is unclear. The primary objective of this review is to determine the diagnostic accuracy of MRI in comparison to surgical brachial plexus exploration for detecting root avulsion in children under 5 with OBPI. The secondary objectives are to determine its' diagnostic accuracy for detecting nerve abnormality and detecting pseudomeningocele(s) in this group.

METHODS

This review will be conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA).We will include studies reporting the accuracy of MRI (index test) compared to surgical exploration (reference standard) in detecting any of the three target conditions (root avulsion, any nerve abnormality and pseudomeningocele) in children under five with OBPI. Case reports and studies where the number of true positives, false positives, true negatives and false negatives cannot be derived will be excluded. We plan to search PubMed, Embase and CENTRAL for relevant studies from database inception to 15 June 2022. We will also search grey literature (medRxiv, bioRxiv and Google Scholar) and perform forward and backward citation chasing. Screening and full-text assessment of eligibility will be conducted by two independent reviewers, who will then both extract the relevant data. The QUADAS-2 tool will be used to assess methodological quality and risk of bias of included studies by two reviewers independently. The following test characteristics for the target conditions will be extracted: true positives, false positives, true negatives and false negatives. Estimates of sensitivity and specificity with 95% confidence intervals will be shown in forest plots for each study. If appropriate, summary sensitivities and specificities for target conditions will be obtained via meta-analyses using a bivariate model.

DISCUSSION

This study will aim to clarify the diagnostic accuracy of MRI for detecting nerve injury in OBPI and define its clinical role.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42021267629.

Radiographic imaging modalities for perinatal brachial plexus palsy: a systematic review

PURPOSE

Perinatal brachial plexus palsy (PBPP) has a wide spectrum of clinical symptoms that can range from incomplete paresis of the affected extremity to flaccid arm paralysis. Although there is a high rate of spontaneous recovery within the first two years of life, it remains challenging to determine which patients will benefit most from surgical intervention. The diagnostic and predictive use of various imaging modalities has been described in the literature, but there is little consensus on approach or algorithm. The anatomic, pathophysiological, and neurodevelopmental characteristics of the neonatal and infant patient population affected by PBPP necessitate thoughtful consideration prior to selecting an imaging modality.

METHODS

A systematic review was conducted using six databases. Two reviewers independently screened articles published through October 2021.

RESULTS

Literature search produced 10,329 publications, and 22 articles were included in the final analysis. These studies included 479 patients. Mean age at time of imaging ranged from 2.1 to 12.8 months and investigated imaging modalities included MRI (18 studies), ultrasound (4 studies), CT myelography (4 studies), and X-ray myelography (1 study). Imaging outcomes were compared against surgical findings (16 studies) or clinical examination (6 studies), and 87.5% of patients underwent surgery.

CONCLUSION

This systematic review addresses the relative strengths and challenges of common radiologic imaging options. MRI is the most sensitive and specific for identifying preganglionic nerve injuries such as pseudomeningoceles and rootlet avulsion, the latter of which has the poorest prognosis in this patient population and often dictates the need for surgical intervention.

Value of High-Resolution MRI in the Diagnosis of Brachial Plexus Injury in Infants and Young Children

Purpose

To investigate the value of high-resolution MRI based on 3D-short inversion time inversion recovery sampling perfection with application-optimized contrasts (3D-STIR SPACE) sequence for the diagnosis of brachial plexus injury in infants and young children.

Methods

Physical examination, electromyography (EMG) and MRI data of 26 children with brachial plexus injury were retrospectively analyzed. Sensitivity, specificity, and accuracy were calculated for the three tests. The agreement among these examinations was analyzed with the Kappa test. P<0.05 was considered statistically significant.

Results

Of the 26 children, 3 cases had normal MRIs, 23 cases had unilateral brachial plexus injury diagnosed with MRI, and a total of 73 nerve roots and/or sheaths were involved. Among the 23 cases with aberrant MRI findings, there were 19 cases of nerve root thickening (42 nerve roots), 4 cases of nerve root sleeve expansion (5 nerve roots), 17 cases of pseudomeningeal cysts (34 nerve roots), 2 cases of nerve root loosening (2 nerve roots), 8 cases of nerve root dissection (11 nerve roots), 19 cases with increased nerve signal (43 nerve roots), and 9 cases with an increased signal of the muscles on the affected side. As for the diagnosis of brachial plexus injury, the sensitivity and the accuracy of physical examination, EMG and MRI were 0.92, 0.86, and 0.88, respectively. The agreement between MRI and physical examination was substantial (κ=0.780, P=0.000), as did the agreement between MRI and EMG (κ=0.611, P=0.005).

Conclusion

High-resolution MRI based on 3D-STIR SPACE sequence plays a role in the diagnosis and evaluation of brachial plexus injury in infants and young children. It can accurately identify the injured nerve and characterize related pathological alterations. Besides EMG and physical examination, it can be used as a valuable tool for screening and monitoring of brachial plexus injury in infants and children.

Brachial Plexus Birth Palsy: Practical Concepts for Radiologists

Brachial plexus birth palsy (BPBP) is classified as a preganglionic or postganglionic injury based on the site of injury. Most patients recover spontaneously and are followed up with clinical evaluation; however, permanent sequelae are not uncommon. For patients with persistent neurologic deficits, clinical and radiologic evaluation is crucial. Untreated BPBP can progress to significant sequelae, such as muscle contractures and glenohumeral dysplasia (GHD). Timely characterization of these entities based on different imaging modalities is a high priority for optimal patient outcomes. We describe the anatomy and pathogenesis, as well as the different imaging modalities involved in the evaluation and classification of BPBP and GHD.

Axial T2-DRIVE MRI myelography is highly accurate in diagnosing preganglionic traumatic brachial plexus injuries: why pseudomeningoceles should not be used as a primary diagnostic sign

AIM

To evaluate the accuracy of brachial plexus magnetic resonance imaging (MRI) utilising the three-dimensional (3D)-T2-turbo spin echo (TSE) with 90° flip-back pulse ("DRIVE") myelography in detecting nerve root avulsions in patients with traumatic brachial plexus injuries.

MATERIALS AND METHODS

A prospective study of 24 patients planned for brachial plexus reconstructive surgery following trauma from April 2019 to October 2021. Preoperative 1.5 T MRI of the brachial plexus was performed utilising axial T2-DRIVE, looking for signs of avulsions (absent dural rootlets, pauci-rootlet appearance and thickened rootlets; the presence of pseudomeningoceles was noted only as an ancillary sign). Comparison against the reference standard of extra-dural brachial plexus exploration was performed. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated.

RESULTS

Eighteen patients had at least one root avulsion at surgery, five showed isolated post-ganglionic injuries, and one had normal brachial plexus exploration. Thirty-nine avulsed roots were found at surgery (out of 108 explored in 24 patients). Preoperative MRI identified the specific avulsed roots accurately in each patient. Two false-positive diagnoses of C5 and C6 avulsions were made in one patient. On MRI, absence of the rootlets was seen in 73.2% (n=30) of avulsions, pauci-rootlet appearance in 24.4% (n=10) and thickening of the rootlets in 2.4% (n=1). Pseudomeningoceles were found only in 68.3% (n=28) of avulsions. The overall sensitivity, specificity, PPV, NPV, and accuracy of MRI were 100%, 97.1%, 95.1%, 100% and 98.1%, respectively.

CONCLUSION

3D-T2-DRIVE is highly accurate in evaluating pre-ganglionic traumatic brachial plexus injuries. Pseudomeningoceles can be considered an ancillary feature of avulsion given the clarity of rootlet visualisation by this sequence.

Magnetic resonance imaging of the brachial plexus. Part 2: Traumatic injuries

The most common indications for magnetic resonance imaging (MRI) of the brachial plexus (BP) are traumatic injuries. The role of MRI of the BP has increased because of recent trends favoring earlier surgery. Determining preganglionic vs. postganglionic injury is essential, as different treatment strategies are required. Thus, MRI of the BP should be supplemented with cervical spine MRI to assess the intradural part of the spinal nerves, including highly T2-weighted techniques. Acute preganglionic injuries usually manifest as various combinations of post-traumatic pseudomeningocele, the absence of roots, deformity of nerve root sleeves, displacement of the spinal cord, hemorrhage in the spinal canal, presence of scars in the spinal canal, denervation of the back muscles, and syrinx. Spinal nerve root absence is more specific than pseudomeningocele on MRI. Acute postganglionic injuries can present as lesions in continuity or tears. The following signs indicate injury to the BP: side-to-side difference, swelling, partial, or total BP rupture. Injury patterns and localization are associated with the mechanism of trauma, which implies a significant role for MRI in the work-up of patients.

The identification and description of traumatic lesions involving the brachial plexus need to be systematic and detailed. Using an appropriate MRI protocol, obtaining details about the injury, applying a systematic anatomical approach, and correlating imaging findings to relevant clinical data to make a correct diagnosis. Information about the presence or suspicion of root avulsion should always be provided.

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Trauma is the most common indication for MRI of the brachial plexus.

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MRI of the brachial plexus should include cervical spine MRI.

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Spinal nerve root absence is seen in preganglionic injuries.

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Determining preganglionic vs. postganglionic injury is essential for treatment planning.

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Appropriate MRI rapport is crucial in communication with the clinician.

Additive value of magnetic resonance neurography in diagnosis of brachial plexopathy: a cross-section descriptive study

Background

Management of brachial plexopathy requires proper localization of the site and nature of nerve injury. Nerve conduction studies and electrophysiological studies (ED) are crucial when diagnosing brachial neuropathy but these do not determine the actual site of the lesion. Conventional MRI has been used to evaluate the brachial plexus. Still, it carried the disadvantage of the inability to provide multi-planar images that depict the entire length of the neural plexus .It might be difficult to differentiate the brachial plexus nerves from adjacent vascular structures. Magnetic resonance neurography (MRN) is an innovative imaging technique for direct imaging of the spinal nerves. Our study aims to detect the additive role of MRN in the diagnosis of brachial plexopathy over ED. Forty cases of clinically suspected and proved by clinical examination and ED—traumatic (N = 30) and non-traumatic (N = 10)—were included in our study. We compared MRN finding with results of clinical examination and ED.

Results

MRN findings showed that the root was involved in 80% of cases, trunks in 70% of cases affecting the middle trunk in 40% of cases, the middle and posterior cord in 25%, lateral cord in 50%, and terminal branches on 10% of cases. Ten percent of cases were normal according to MRN, and 90% had abnormal findings in the form of preganglionic nerve root avulsion in 30% of cases, mild perineural edema surrounding C6/7 nerve roots in 20%, lower brachial trunk high signal in 10%, complicated with pseudo meningocele in 20%, and with increased shoulder muscle T2 signal intensity with muscle atrophy in 10%. There were minimal differences between clinical examination finding and MRN findings, with very good agreement between electromyography and nerve conduction (p value < 0.05, with sensitivity and specificity values of 94.44% and 100%, respectively).

Conclusion

MRN is important in differentiating different types of nerve injuries, nerve root avulsion, and nerve edema, playing an important role in differentiating the site of nerve injury, both preganglionic or postganglionic and planning for treatment of the cause of nerve injury, either medical or surgical.

A Systematic Review of the Tensile Biomechanical Properties of the Neonatal Brachial Plexus

Brachial plexus (BP) birth injury has a reported incidence of 1 to 4 per 1000 live births. During complicated deliveries, neonatal, maternal, and other birth-related factors can cause over-stretching or avulsion of the neonatal brachial plexus leading to injury. Understanding biomechanical responses of the neonate brachial plexus when subjected to stretch can offer insight into the injury outcomes while guiding the development of preventative maneuvers that can help reduce the occurrence of neonatal brachial plexus injuries. This review article aims to offer a comprehensive overview of existing literature reporting biomechanical responses of the brachial plexus, in both adults and neonates, when subjected to stretch. Despite the discrepancies in the reported biomechanical properties of the brachial plexus, available studies confirm the loading rate and loading direction dependency of the brachial plexus tissue. Future studies, possibly in vivo, that utilize clinically relevant neonatal large animal models can provide translational failure values of the biomechanical parameters for the neonatal brachial plexus when subjected to stretch.

MRI evaluation of nerve root avulsion in neonatal brachial plexus palsy: understanding the presence of isolated dorsal/ventral rootlet disruption

OBJECTIVE

The evaluation, treatment, and prognosis of neonatal brachial plexus palsy (NBPP) continues to have many areas of debate, including the use of ancillary testing. Given the continued improvement in imaging, it is important to revisit its utility. Nerve root avulsions have historically been identified by the presence of pseudomeningoceles or visible ruptures. This "all-or-none" definition of nerve root avulsions has many implications for the understanding and management of NBPP, especially as characterization of the proximal nerve root as a potential donor remains critical. This study examined the ability of high-resolution MRI to more specifically define the anatomy of nerve root avulsions by individually examining the ventral and dorsal rootlets as they exit the spinal cord.

METHODS

This is a retrospective review of patients who had undergone brachial plexus protocol MRI for clinical evaluation of NBPP at a single institution. Each MR image was independently reviewed by a board-certified neuroradiologist, who was blinded to both established diagnosis/surgical findings and laterality. Each dorsal and ventral nerve rootlet bilaterally from C5 to T1 was evaluated from the spinal cord to its exit in the neuroforamen. Each rootlet was classified as avulsed, intact, or undeterminable.

RESULTS

Sixty infants underwent brachial plexus protocol MRI from 2010 to 2018. All infants were included in this study. Six hundred individual rootlets were analyzed. There were 49 avulsed nerve rootlets in this cohort. Twenty-nine (59%) combined dorsal/ventral avulsions involved both the ventral and dorsal rootlets, and 20 (41%) were either isolated ventral or isolated dorsal rootlet avulsions. Of the isolated avulsion injuries, 13 (65%) were dorsal only, meaning that the motor rootlets were intact.

CONCLUSIONS

A closer look at nerve root avulsions with MRI demonstrates a significant prevalence (approximately 41%) of isolated dorsal or ventral nerve rootlet disruptions. This finding implies that nerve roots previously labeled as "avulsed" but with only isolated dorsal (sensory) rootlet avulsion can yet provide donor fascicles in reconstruction strategies. A majority (99%) of the rootlets can be clearly visualized with MRI. These findings may significantly impact the clinical understanding of neonatal brachial plexus injury and its treatment.

Team Approach: Management of Brachial Plexus Birth Injury

Brachial plexus birth injury is an upper-extremity paralysis that occurs from a traction injury to the brachial plexus during birth. Approximately 10% to 30% of children with a brachial plexus birth injury have residual neurologic deficits with associated impact on upper-limb function. Management of brachial plexus birth injuries with a multidisciplinary team allows optimization of functional recovery while avoiding unnecessary intervention. Early occupational therapy should be initiated with a focus on range of motion and motor learning. The need for microsurgical reconstruction of the brachial plexus can be predicted based on early physical examination findings, and reconstruction is generally performed at 3 to 9 months of age. The majority of children with residual neurologic deficits develop associated glenohumeral dysplasia. These children may require secondary procedures, including botulinum toxin injection, subscapularis and pectoralis lengthening, shoulder capsular release, shoulder tendon transfer, and humeral osteotomy.

Imaging of Damaged Nerves

Nerve imaging is an important component in the assessment of patients presenting with suspected peripheral nerve pathology. Although magnetic resonance neurography and ultrasound are the most commonly utilized techniques, several promising new modalities are on the horizon. Nerve imaging is useful in localizing the nerve injury, determining the severity, providing prognostic information, helping establish the diagnosis, and helping guide surgical decision making. The focus of this article is imaging of damaged nerves, focusing on nerve injuries and entrapment neuropathies.

Clinical significance of cervical MRI in brachial plexus birth injury

Background and purpose - Patient selection for nerve surgery in brachial plexus birth injury (BPBI) is difficult. Decision to operate is mostly based on clinical findings. We assessed whether MRI improves patient selection. Patients and methods - 157 BPBI patients were enrolled for a prospective study during 2007-2015. BPBI was classified at birth as global plexus injury (GP) or upper plexus injury (UP). The global plexus injury was subdivided into flail upper extremity (FUE) and complete plexus involvement (CP). Patients were seen at set intervals. MRI was scheduled for patients that had either GP at 1 month of age or UP with no antigravity biceps function by 3 months of age. Type (total or partial avulsion, thinned root), number and location of root injuries and pseudomeningoceles (PMC) were registered. Position of humeral head (normal, subluxated, dislocated) and glenoid shape (normal, posteriorly rounded, pseudoglenoid) were recorded. Outcome was assessed at median 4.5 years (1.6-8.6) of age. Results - Cervical MRI was performed on 34/157 patients at median 3.9 months (0.3-14). Total root avulsions (n = 1-3) were detected on MRI in 12 patients (8 FUE, 4 CP). Reconstructive surgery was performed on 10/12 with total avulsions on MRI, and on all 10 with FUE at birth. Sensitivity and specificity of MRI in detecting total root avulsions was 0.88 and 1 respectively. Posterior shoulder subluxation/dislocation was seen in 15/34 patients (3.2-7.7 months of age). Interpretation - Root avulsion(s) on MRI and flail upper extremity at birth are both good indicators for nerve surgery in brachial plexus birth injury. Shoulder pathology develops very early in permanent BPBI.

Clinical Value and Diagnostic Accuracy of 3.0T Multi-Parameter Magnetic Resonance Imaging in Traumatic Brachial Plexus Injury

Background

The aim of this study was to evaluate the clinical value and diagnostic accuracy of 3.0T multi-parameter magnetic resonance imaging (MRI) in traumatic brachial plexus injury.

Material/Methods

Twenty-five healthy volunteers and 28 patients with clinically confirmed traumatic brachial plexus injury were enrolled in this study. Bilateral brachial plexus imaging was performed using conventional sequences (T1WI, T2WI), short time inversion recovery (STIR), balanced fast field echo (balance-FFE), and diffusion weighted imaging with background suppression (DWIBS). The MRI diagnosis was compared with intraoperative electromyography and surgery.

Results

Brachial plexus injuries were classified based on the anatomic locations. There were 16 patients with pre-ganglionic injury and 12 patients with post-ganglionic injury. The pre-ganglionic injury included ruptured nerve roots, stiff nerve roots, traumatic meningeal cysts, black line sign, spinal cord edema, and thickened nerve root sleeve. The post-ganglionic injury included thickened nerve roots, disappearance of normal nerve root structure or disrupted continuity of the nerve, stiff nerve roots, pseudo-neuroma, and abnormalities in the adjacent soft tissues. Comparing the results from MRI and surgery, the sensitivity, specificity, and accuracy of MRI examination were 93.55%, 71.43%, and 89.47% respectively for preganglionic injury, and 91.30%, 60.00%, and 85.71% respectively for postganglionic injury.

Conclusions

The combination of STIR, balance-FFE, and DWIBS sequences can display brachial plexus pre-ganglionic and post-ganglionic injury clearly, effectively, and accurately.

Comparative accuracies of electrodiagnostic and imaging studies in neonatal brachial plexus palsy

OBJECTIVEThe incorporation of ancillary testing in the preoperative setting for patients with neonatal brachial plexus palsy (NBPP) remains controversial, but the recommendation for early nerve reconstruction when a baby has a preganglionic lesion at the lower nerve roots is generally accepted. At some specialty centers, nerve surgeons use preoperative electrodiagnostic testing (EDX) and imaging to aid in lesion localization and the preoperative planning of the nerve reconstruction. EDX and imaging have been evaluated for their abilities to detect pre- and postganglionic lesions, but their accuracies have never been compared directly in the same set of patients. The aim of the present study was to evaluate the accuracy of imaging and EDX in an NBPP population.METHODSA retrospective review was conducted of 54 patients with operative NBPP seen between 2007 and 2017. The patients underwent EDX and imaging: EDX was performed, and the results were reviewed by board-certified electrodiagnosticians, and imaging was reviewed by board-certified neuroradiologists. The gold standard was considered to be the findings at surgical exploration. Descriptive and analytical statistics were utilized to compare the accuracies of imaging and EDX.RESULTSThe mean age at surgery was 6.94 mos (± 4 mos). Fifteen patients (28%) were Narakas grade I-II, and 39 (72%) were Narakas grade III-IV. For all nerve roots, the overall accuracy of detecting preganglionic lesions was 74% for EDX and 69% for imaging. The overall sensitivity of detecting preganglionic lesions by EDX was 31%, but the specificity was 90%. The overall sensitivity of detecting preganglionic lesions by imaging was 66%, and the overall specificity was 70%. However, at C8, EDX was 37.5% sensitive and 87.5% specific, whereas imaging was 67.7% sensitive but only 29.4% specific.CONCLUSIONSEDX outperformed imaging with regard to specificity and accuracy of identifying preganglionic injuries. This finding is especially relevant in the lower nerve roots, given that lower plexus preganglionic lesions are an accepted indication for early intervention.

Adding Value to the Magnetic Resonance Examination in a Case of Brachial Plexus Birth Palsy

We report a case of brachial plexus birth palsy in an infant with the inability to move the left upper limb since birth. There was neither history of birth trauma nor any complications during delivery. Magnetic resonance imaging (MRI) of brachial plexus showed postganglionic injury with musculoskeletal abnormalities. The child underwent surgical repair of the plexus and is on physical rehabilitation. In this case report, we discuss the utility of a single MRI examination with an elaborate discussion on various MRI signs of brachial plexus injury including secondary musculoskeletal manifestations. The case reiterates the significance of two-in-one approach while imaging these cases with MRI. Apart from reporting the damage to the brachial plexus, the radiologist should actively search for glenohumeral dysplasia. Awareness of classification and assessment of glenohumeral dysplasia should be routinely included as an integral part of imaging report as it adds incremental value to the overall patient management and functional outcome.

An Update on the Management of Neonatal Brachial Plexus Palsy-Replacing Old Paradigms: A Review

IMPORTANCE

Neonatal brachial plexus palsy (NBPP) can result in persistent deficits for those who develop it. Advances in surgical technique have resulted in the availability of safe, reliable options for treatment. Prevailing paradigms include, "all neonatal brachial plexus palsy recovers," "wait a year to see if recovery occurs," and "don't move the arm." Practicing by these principles places these patients at a disadvantage. Thus, the importance of this review is to provide an update on the management of NBPP to replace old beliefs with new paradigms.

OBSERVATIONS

Changes within denervated muscle begin at the moment of injury, but without reinnervation become irreversible 18 to 24 months following denervation. These time-sensitive, irreversible changes are the scientific basis for the recommendations herein for the early management of NBPP and put into question the old paradigms. Early referral has become increasingly important because improved outcomes can be achieved using new management algorithms that allow surgery to be offered to patients unlikely to recover sufficiently with conservative management. Mounting evidence supports improved outcomes for appropriately selected patients with surgical management compared with natural history. Primary nerve surgery options now include nerve graft repair and nerve transfer. Specific indications continue to be elucidated, but both techniques offer a significant chance of restoration of function.

CONCLUSIONS AND RELEVANCE

Mounting data support both the safety and effectiveness of surgery for patients with persistent NBPP. Despite this support, primary nerve surgery for NBPP continues to be underused. Surgery is but one part of the multidisciplinary care of NBPP. Early referral and implementation of multidisciplinary strategies give these children the best chance of functional recovery. Primary care physicians, nerve surgeons, physiatrists, and occupational and physical therapists must partner to continue to modify current treatment paradigms to provide improved quality care to neonates and children affected by NBPP.

MR neurography in traumatic, non-obstetric paediatric brachial plexopathy

OBJECTIVES

Many studies have elaborated on the role of magnetic resonance neurography (MRN) in evaluating traumatic brachial plexopathies. Most of these deal with MR findings in adult traumatic plexopathies or children with obstetric brachial plexus palsy (OBPP). Hence, the authors felt the need for this particular study, which focuses on MRN findings in children with non-obstetric traumatic brachial plexus palsy, to find out the distribution and severity of injuries in these patients.

METHODS

This was a single-institution, prospective study conducted between April 2015 and June 2016. All children presenting to the hospital with features of brachial plexopathy and a history of non-obstetric trauma were included in the study.

RESULTS

At MRN, we looked for signs of injury at three levels: roots, trunks and cords. Signs of injury were found at the level of the roots in 22 patients (88%), at the level of the trunks in 20 patients (80%) and at the level of the cords in 22 patients (88%).

CONCLUSIONS

This study, conducted on children suffering from non-obstetric, traumatic brachial plexopathy returned some interesting conclusions including that when the paediatric plexus is injured, the injury is severe and multi-level, with a very high incidence of root injuries.

KEY POINTS

• Brachial plexus injury in paediatric age group is a devastating injury. • The most common cause of this is trauma sustained during birth. • Other causes include road traffic accidents and blunt injury. • MR neurography has revolutionised the diagnosis of brachial plexopathy.

Differentiation of Pre- and Postganglionic Nerve Injury Using MRI of the Spinal Cord

Brachial plexus injury (BPI) is a devastating type of nerve injury, potentially causing loss of motor and sensory function. Principally, BPI is either categorized as preganglionic or postganglionic, with the early establishment of injury level being crucial for choosing the correct treatment strategy. Despite diagnostic advances, the need for a reliable, non-invasive method for establishing the injury level remains. We studied the usefulness of in vivo magnetic resonance imaging (MRI) of the spinal cord for determination of injury level. The findings were related to neuronal and glial changes. Rats underwent unilateral L4 & L5 ventral roots avulsion or sciatic nerve axotomy. The injuries served as models for pre- and postganglionic BPI, respectively. MRI of the L4/L5 spinal cord segments 4 weeks after avulsion showed ventral horn (VH) shrinkage on the injured side compared to the uninjured side. Axotomy induced no change in the VH size on MRI. Following avulsion, histological sections of L4/L5 revealed shrinkage in the VH grey matter area occupied by NeuN-positive neurons, loss of microtubular-associated protein-2 positive dendritic branches (MAP2), pan-neurofilament positive axons (PanNF), synaptophysin-positive synapses (SYN) and increase in immunoreactivity for the microglial OX42 and astroglial GFAP markers. Axotomy induced no changes in NeuN-reactivity, modest decrease of MAP2 immunoreactivity, no changes in SYN and PanNF labelling, and a modest increase in OX42 and SYN labeling. Histological and radiological findings were congruent when assessing changes after axotomy, while MRI somewhat underestimated the shrinkage. This study indicates a potential diagnostic value of structural spinal cord MRI following BPI.

Interrater reliability of electrodiagnosis in neonatal brachial plexopathy

INTRODUCTION

We investigated interrater reliability of overall assessment of nerve root lesions by electrodiagnostic testing (EDX) in neonatal brachial plexus palsy (NBPP).

METHODS

Two blinded, board-certified reviewers retrospectively reviewed de-identified EDX data from 37 infants with NBPP for 2005-2012. Only nerve conduction and electromyography needle data were included. The examiners independently assigned 1 of 4 nerve root lesion categories: (1) pre-ganglionic lesion (avulsion), (2) post-ganglionic lesion (rupture), (3) normal, or (4) "unable to determine." Simple percentage agreement, the Cohen kappa statistic representing interrater reliability for each nerve root (C5-T1), and overall kappa between examiners were evaluated.

RESULTS

Interrater reliabilities were substantial to almost perfect for each nerve root except C5. Considering all nerve roots, overall interrater reliability was substantial (kappa = 0.62); simple percentage agreement was 75% (138/185).

CONCLUSIONS

Interrater reliability of nerve root assessment by EDX for infants with NBPP was high for C6-T1 root levels, but less reliable for C5 because of technical factors. Muscle Nerve 55: 69-73, 2017.

Recovery of upper extremity function following endoscopically assisted contralateral C7 transfer for obstetrical brachial plexus injury

Transfer of the contralateral C7 nerve for reconstruction of the brachial plexus in infants with obstetrical brachial plexus injury has rarely been reported. We developed a new endoscopy-assisted technique via the prevertebral (retroesophageal) route for the transfer of the contralateral C7 nerve in reconstruction of the brachial plexus. The reconstruction was performed in 20 infants (14 boys and six girls). Motor recovery was assessed using the Gilbert and Raimondi scales. The Narakas Sensory Grading System was used to evaluate hand sensation. The mean follow-up period was 45 months (SD 18.2). Of the 20 children, nine had contralateral C7 transfer to lower nerve roots, two had transfer to upper nerve roots and nine had transfer to both upper and lower roots. The postoperative shoulder and elbow functions were good or satisfactory according to the Gilbert classification in all children whose preoperative scores were poor. All patients with lower roots reconstruction (9) had satisfactory hand function. A total of 15 children had a Narakas score of S3. Our technique enables safe contralateral C7 transfer to the avulsed roots in severe obstetrical brachial plexus injury infants with a satisfactory functional recovery.

LEVEL OF EVIDENCE

Level IV.

Non-Sedated Rapid Volumetric Proton Density MRI Predicts Neonatal Brachial Plexus Birth Palsy Functional Outcome

BACKGROUND AND PURPOSE

The current prognostic biomarker of functional outcome in brachial plexus birth palsy is serial clinical examination throughout the first 6 months of age. This can delay surgical treatment and prolong parental anxiety in neonates who will recover spontaneously. A potentially superior biomarker is a volumetric proton density MRI performed at clinical presentation and within the first 12 weeks of life, providing a high spatial and contrast resolution examination in 4 minutes.

METHODS

Nine neonates ranging in age from 4 to 9 weeks who presented with brachial plexus birth palsy were enrolled. All subjects underwent non-sedated 3 Tesla MRI with Cube Proton Density MRI sequence at the same time as their initial clinical visit. Serial clinical examinations were conducted at routine 4 week intervals and the functional performance scores were recorded. MRI findings were divided into pre-ganglionic and post-ganglionic injuries and a radiological scoring system (Shriners Radiological Score) was developed for this study.

RESULTS

Proton Density MRI was able to differentiate between pre-ganglionic and post-ganglionic injuries. Radiological scores (Shriners Radiological Score) correlated better with functional performance at 6 months of age (P = .022) than the initial clinical examinations (Active Movement Scale P = .213 and Toronto P = .320).

CONCLUSIONS

Rapid non-sedated volumetric Cube Proton Density MRI protocol performed at initial clinical presentation can accurately grade severity of brachial plexus birth palsy injury and predict functional performance at 6 months of age.

The current role of diagnostic imaging in the preoperative workup for refractory neonatal brachial plexus palsy

INTRODUCTION

Despite recent improvements in perinatal care, the incidence of neonatal brachial plexus palsy (NBPP) remains relatively common. CT myelography is currently considered to be the optimal imaging modality for evaluating nerve root integrity. Recent improvements in MRI techniques have made it an attractive alternative to evaluate nerve root avulsions (preganglionic injuries).

AIM

We demonstrate the utility of MRI for the evaluation of normal and avulsed spinal nerve roots. We also show the utility of ultrasound in providing useful preoperative evaluation of the postganglionic brachial plexus in patients with NBPP.

Utility of ultrasound in noninvasive preoperative workup of neonatal brachial plexus palsy

BACKGROUND

Ultrasound has been utilized in the evaluation of compressive and traumatic peripheral nerve pathology.

OBJECTIVE

To determine whether US can provide comprehensive evaluation of the post-ganglionic brachial plexus in the setting of neonatal brachial plexus palsy and whether this information can be used to guide preoperative nerve reconstruction strategies.

MATERIALS AND METHODS

In this retrospective cohort study, preoperative brachial plexus ultrasonography was performed in 52 children with neonatal brachial plexus palsy who were being considered for surgery. The 33 children who had surgery compose the patient cohort. The presence and location of post-ganglionic neuromas were evaluated by US and compared to the surgical findings. US evaluation of shoulder muscle atrophy was conducted as an indirect way to assess the integrity of nerves. Finally, we correlated glenohumeral joint laxity to surgical and clinical management.

RESULTS

Ultrasound correctly identified 21 of 25 cases of upper trunk and middle trunk neuroma involvement (84% sensitivity for each). It was 68% sensitive and 40% specific in detection of lower trunk involvement. US identified shoulder muscle atrophy in 11 of 21 children evaluated; 8 of these 11 went on to nerve transfer procedures based upon the imaging findings. US identified 3 cases of shoulder joint laxity of the 13 children evaluated. All 3 cases were referred for orthopedic evaluation, with 1 child undergoing shoulder surgery and another requiring casting.

CONCLUSION

Ultrasound can provide useful preoperative evaluation of the post-ganglionic brachial plexus in children with neonatal brachial plexus palsy.

Peripartum and neonatal factors associated with the persistence of neonatal brachial plexus palsy at 1 year: a review of 382 cases

OBJECTIVE Neonatal brachial plexus palsy (NBPP) occurs due to the stretching of the nerves of the brachial plexus before, during, or after delivery. NBPP can resolve spontaneously or become persistent. To determine if nerve surgery is indicated, predicting recovery is necessary but difficult. Historical attempts explored the association of recovery with only clinical and electrodiagnostic examinations. However, no data exist regarding the neonatal and peripartum factors associated with NBPP persistence. METHODS This retrospective cohort study involved all NBPP patients at the University of Michigan between 2005 and 2015. Peripartum and neonatal factors were assessed for their association with persistent NBPP at 1 year, as defined as the presence of musculoskeletal contractures or an active range of motion that deviated from normal by > 10° (shoulder, elbow, hand, and finger ranges of motion were recorded). Standard statistical methods were used. RESULTS Of 382 children with NBPP, 85% had persistent NBPP at 1 year. A wide range of neonatal and peripartum factors was explored. We found that cephalic presentation, induction or augmentation of labor, birth weight > 9 lbs, and the presence of Horner syndrome all significantly increased the odds of persistence at 1 year, while cesarean delivery and Narakas Grade I to II injury significantly reduced the odds of persistence. CONCLUSIONS Peripartum/neonatal factors were identified that significantly altered the odds of having persistent NBPP at 1 year. Combining these peripartum/neonatal factors with previously published clinical examination findings associated with persistence should allow the development of a prediction algorithm. The implementation of this algorithm may allow the earlier recognition of those cases likely to persist and thus enable earlier intervention, which may improve surgical outcomes.

Nerve transfers and neurotization in peripheral nerve injury, from surgery to rehabilitation

Peripheral nerve injury (PNI) and recent advances in nerve reconstruction (such as neurotization with nerve transfers) have improved outcomes for patients suffering peripheral nerve trauma. The purpose of this paper is to bridge the gap between the electromyographer/clinical neurophysiologist and the peripheral nerve surgeon. Whereas the preceding literature focuses on either the basic science behind nerve injury and reconstruction, or the surgical options and algorithms, this paper demonstrates how electromyography is not just a 'decision tool' when deciding whether to operate but is also essential to all phases of PNI management including surgery and rehabilitation. The recent advances in the reconstruction and rehabilitation of PNI is demonstrated using case examples to assist the electromyographer to understand modern surgical techniques and the unique demands they ask from electrodiagnostic testing.

Neuropathological Characteristics of Brachial Plexus Avulsion Injury With and Without Concomitant Spinal Cord Injury

Neonatal brachial plexus avulsion injury (BPAI) commonly occurs as a consequence of birth trauma and can result in lifetime morbidity; however, little is known regarding the evolving neuropathological processes it induces. In particular, mechanical forces during BPAI can concomittantly damage the spinal cord and may contribute to outcome. Here, we describe the functional and neuropathological outcome following BPAI, with or without spinal cord injury, in a novel pediatric animal model. Twenty-eight-day-old piglets underwent unilateral C5–C7 BPAI with and without limited myelotomy. Following avulsion, all animals demonstrated right forelimb monoparesis. Injury extending into the spinal cord conferred greater motor deficit, including long tract signs. Consistent with clinical observations, avulsion with myelotomy resulted in more severe neuropathological changes with greater motor neuron death, progressive axonopathy, and persistent glial activation. These data demonstrate neuropathological features of BPAI associated with poor functional outcome. Interestingly, in contrast to adult small animal models of BPAI, a degree of motor neuron survival was observed, even following severe injury in this neonatal model. If this is also the case in human neonatal BPAI, repair may permit functional restoration. This model also provides a clinically relevant platform for exploring the complex postavulsion neuropathological responses that may inform therapeutic strategies.

Clinical assessment of the infant and child following perinatal brachial plexus injury

STUDY DESIGN

Literature review.

INTRODUCTION

After perinatal brachial plexus injury (PBPI), clinicians play an important role in injury classification as well as the assessment of recovery and secondary conditions. Early assessment guides the initial plan of care and influences follow-up and long-term outcome.

PURPOSE

To review methods used to assess, classify and monitor the extent and influence of PBPI with an emphasis on guidelines for clinicians.

METHODS

We use The International Classification of Functioning, Disability, and Health (ICF) model to provide a guide to assessment after PBPI for rehabilitation clinicians.

DISCUSSION

With information gained from targeted assessments, clinicians can design interventions to increase the opportunities infants and children have for optimal recovery and to attain skills that allow participation in areas of interest.