Adult traumatic brachial plexus injury

Case-based report of graded motor imagery experience in traumatic brachial plexus injury: The art of moving without moving

BACKGROUND

We reported a 24-year-old woman who sustained multiple upper limb injuries after a traffic accident in March 2017. She sustained a C7-T1 brachial plexus injury and radial nerve injury on the left side diagnosed in November 2017. The patient underwent radial nerve reconstruction. The patient began her comprehensive therapy program in January 2018.

PURPOSE

To describe the use of graded motor imagery (GMI) and outcomes after traumatic brachial plexus palsy. We presented changes in electromyographic (EMG) activity of target muscles during task execution and functional status following 10-session GMI therapy.

STUDY DESIGN

Case report.

METHODS

The program included 4 sessions of motor imagery and 6 sessions of a combination of motor imagery and mirror therapy.

RESULTS

The patient successfully participated in the program with reported improvements in EMG activity, functional status, emotional well-being, and body awareness.

CONCLUSIONS

GMI therapy appears to have peripheral motor effects, including altered surface EMG activity and contributes to a favorable outcome in the functional level of the affected arm. An improved emotional state and awareness of the affected hand could have a positive effect on function. Future long-term randomized controlled trials are needed to investigate the cumulative peripheral effects of treatment of graded motor imagery and the effects of variables mediating its effects on functional performance in patients with nerve injury.

Neurophysiological Evaluation of Neural Transmission in Brachial Plexus Motor Fibers with the Use of Magnetic versus Electrical Stimuli

The anatomical complexity of brachial plexus injury requires specialized in-depth diagnostics. The clinical examination should include clinical neurophysiology tests, especially with reference to the proximal part, with innovative devices used as sources of precise functional diagnostics. However, the principles and clinical usefulness of this technique are not fully described. The aim of this study was to reinvestigate the clinical usefulness of motor evoked potential (MEP) induced by a magnetic field applied over the vertebrae and at Erb's point to assess the neural transmission of brachial plexus motor fibers. Seventy-five volunteer subjects were randomly chosen to participate in the research. The clinical studies included an evaluation of the upper extremity sensory perception in dermatomes C5-C8 based on von Frey's tactile monofilament method, and proximal and distal muscle strength by Lovett's scale. Finally, 42 healthy people met the inclusion criteria. Magnetic and electrical stimuli were applied to assess the motor function of the peripheral nerves of the upper extremity and magnetic stimulus was applied to study the neural transmission from the C5-C8 spinal roots. The parameters of compound muscle action potential (CMAP) recorded during electroneurography and MEP induced by magnetic stimulation were analyzed. Because the conduction parameters for the groups of women and men were comparable, the final statistical analysis covered 84 tests. The parameters of the potentials generated by electrical stimulus were comparable to those of the potentials induced by magnetic impulse at Erb's point. The amplitude of the CMAP was significantly higher following electrical stimulation than that of the MEP following magnetic stimulation for all the examined nerves, in the range of 3-7%. The differences in the potential latency values evaluated in CMAP and MEP did not exceed 5%. The results show a significantly higher amplitude of potentials after stimulation of the cervical roots compared to potentials evoked at Erb's point (C5, C6 level). At the C8 level, the amplitude was lower than the potentials evoked at Erb's point, varying in the range of 9-16%. We conclude that magnetic field stimulation enables the recording of the supramaximal potential, similar to that evoked by an electric impulse, which is a novel result. Both types of excitation can be used interchangeably during an examination, which is essential for clinical application. Magnetic stimulation was painless in comparison with electrical stimulation according to the results of a pain visual analog scale (3 vs. 5.5 on average). MEP studies with advanced sensor technology allow evaluation of the proximal part of the peripheral motor pathway (between the cervical root level and Erb's point, and via trunks of the brachial plexus to the target muscles) following the application of stimulus over the vertebrae.

Clinical and functional outcome after different surgical approaches for brachial plexus injuries: Cohort study

Introduction

Brachial plexus injury (BPI) can result in complete loss of neurological function and reduces the quality of life. Nerve transfer, nerve grafting, external neurolysis, and free functional muscle transfer are several management options that determine the eventual outcomes. Despite various methods of treatment, hardly any literature compares directly the result of these treatment options. This study aimed to analyze differences in clinical and functional outcomes after a reconstructive surgery.

Methods

A cohort retrospective study was conducted on traumatic brachial plexus injured patients aged from 17 to 65 years at one hospital in Surabaya, Indonesia, from January 2009 to December 2019. All patients were divided into 4 groups depending on the types of surgery. The clinical outcomes were measured using elbow and shoulder muscle strength, elbow and shoulder range of motion (ROM), and pain level (measured using Visual Analog Scale/VAS); the functional outcomes were measured using the overall quality of life using the DASH (disabilities of the arms, shoulder, and hand) score.

Results

This study included 316 patients comprising of 256 males with an average age of 27.53 ± 11.37, an average time from injury to surgery of 17.74 ± 35.82 months, and average follow-up duration of 59.89 ± 37.68 months. Most cases were caused by road traffic accidents (77.22%) and most were total arm type of BPI injury (70.7%). There was no significant difference in the mean values of study parameters except in VAS (p = 0.042) as nerve grafting resulted in less pain than external neurolysis (2.27 ± 1.03 vs. 3.68 ± 1.93, respectively; p = 0.017). Besides, nerve transfer procedure also resulted in less pain compared to external neurolysis (2.99 ± 1.84 vs. 3.68 ± 1.93, respectively; p = 0.036).

Conclusion

We found no significant difference between types of surgery and the postsurgical outcome. A wider multicenter study was required to define the clinical and functional outcomes clearly.

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.

Preoperative imaging assessment of the paralytic upper limb

Imaging has become an essential tool in the study of the posttraumatic paralytic upper limb, in addition to the clinical examination and electroneuromyography. Upper extremity surgeons must be aware of how these different techniques contribute to the initial and preoperative assessment of nervous injuries. We review the appearance of traumatic nerve damage and muscle denervation during the initial injury assessment, focusing on the main aspects of brachial plexus injuries, paralysis after shoulder dislocation and traumatic damage to the radial nerve. Finally, we discuss the role of imaging for preoperative assessment of musculotendinous and osteoarticular palliative surgeries.

Carpal tunnel syndrome or C8/T1 radiculoneuropathy due to perinural cyst: A diagnostic conundrum

Perineural cysts are usually described in Lumbosacral region and are uncommonly seen in cervical spine. These are mostly asymptomatic, with only a few cases of symptomatic cervical perineural cysts. No previous case report of perineural cyst causing C8/T1 radiculoneuropathy mimicking clinically as Carpal tunnel syndrome is reported in the literature. We report a case of elderly female who was operated for presumed Carpal tunnel syndrome. However, her symptoms did not improve. The MRI of the patient revealed presence of perineural cysts at the level of C8/T1 exiting nerve root, compressing it and causing the symptoms. We present the clinical, nerve conduction study and radiological presentation of cervical perineural cyst mimicking Carpal tunnel syndrome in this patient.

The importance of early and long-lasting medical rehabilitation in patients with brachial plexus injury

Introduction. Brachial plexus lesions vary in severity, depending on the etiopathogenic mechanism and the level of force to which the plexus is exposed. In the same patient, several nerves of the plexus can be damaged in varying degrees of severity. Brachial plexus injuries lead to upper limb paralysis and disability. Material and Methods. We present the case of a 68-year-old woman diagnosed a year ago with multiple myeloma, clavicular plasmacytoma and secondary spontaneous clavicle fracture. At the same time she presented several dislocations of the shoulder and was diagnosed with brachial plexus palsy after the last dislocation. The patient was hospitalized in our department with a large motor deficit in the upper limb. A comprehensive motor rehabilitation program has been established three weeksafter installing the palsy. Results and discussion. The evolution of the patient was favorable. It was noticed the reduction of the symptoms and slight improvement in motor deficit of the affected upper limb. Thepatient rehabilitation should continue for several months because the nerve regenerates slowly. Conclusion. In patients with brachial plexus injury, motor rehabilitation should be instituted as early as possible and continued for a longer periodoftime until nerve regeneration occurs.It results that early and continuous medical rehabilitation is essential in patients with brachial plexus injury. Keywords: Brachial plexus injury, shoulder dislocation, rehabilitation,

[COVID-19 and plastic surgery: aesthetic surgery or essential medical care? - Impact of the COVID-19 pandemic on patient care in the plastic surgery department at an university hospital]

Einleitung  Im Frühjahr 2020 machte die COVID-19-Pandemie weitreichende Veränderungen und Maßnahmen in bisher nie dagewesenem Ausmaß notwendig. Diese Maßnahmen zielten einerseits darauf ab die Ausbreitung der Virusinfektion einzudämmen, und andererseits die landesweite Krankenversorgung weiterhin zu gewährleisten, insbesondere um im Falle einer größeren Anzahl an mit COVID-19 infizierten Patienten ausreichend Intensivkapazitäten zur Verfügung zu haben. In Bezug auf operative Fächer bedeutete dies das temporäre Aussetzen des Elektivprogramms auf unbestimmte Zeit. Ziel dieser Studie war es die Auswirkung dieser Maßnahmen auf das Behandlungsspektrum eines plastisch-chirurgischen Zentrums zu evaluieren.

Methode  Die Operationszahlen der klinischen Abteilung für Plastische, Ästhetische und Rekonstruktive Chirurgie der medizinischen Universität Graz während des sog. Lockdowns von 16.3.2020 bis 26.4.2020 (6 Wochen) sowie 2 Wochen davor wurden retrospektiv erhoben. Die Daten wurden zum korrespondierende Vorjahreszeitraum verglichen. Untersucht wurden u. a. Operationsspektrum, Dringlichkeit, Indikation und Komplikationsraten.

Ergebnisse  Durch den Wegfall des Elektivprogramms kam es während des Lockdowns im Jahresvergleich zu einem signifikanten Rückgang der OP-Zahlen um 57,5 % (2019: 353, 2020 150 Fälle). Während des Lockdowns wurden im Jahresvergleich signifikant mehr Notfall- und Akuteingriffe durchgeführt (2019: 41, 2020: 58 Fälle, p < 0,001). Außerdem wurde eine signifikante Häufung von Selbstverletzungen bzw. Suizidversuchen beobachtet (2019: 0, 2020: 16 Fälle, p > 0,001). Hinsichtlich Privat- und Arbeitsunfällen gab es keine signifikanten Unterschiede. Es zeigte sich auch kein signifikanter Unterschied bezüglich der Komplikationsrate (2019: 6,8, 2020: 10 %, p = 0,219).

Zusammenfassung  Ein signifikanter Anteil plastisch-chirurgischer Operationen an einem Universitätsklinikum mit überregionalem Versorgungsauftrag besteht aus Notfalloperationen, akuten und dringenden medizinisch notwendigen Operationen. Während des Lockdowns wurden Operationen ohne signifikanten Anstieg der Komplikationsrate durchgeführt. Trotz sämtlicher Herausforderungen während der Pandemie konnte eine qualitativ konstante Patientenversorgung auf höchstem Niveau gewährleistet werden. Um die während des Lockdowns angehäuften weniger dringenden, jedoch ebenso wichtigen Fälle zeitgerecht und in entsprechend hoher Qualität abzuarbeiten, wird eine Erweiterung der Operationskapazitäten mit Steigerung der Bettenanzahl und der Ambulanzkapazität notwendig sein. Die vorliegenden Ergebnisse zeigen, wie wichtig die Plastische Chirurgie für die medizinische Versorgung insbesondere in Krisenzeiten ist.

High-resolution in vivo MR imaging of intraspinal cervical nerve rootlets at 3 and 7 Tesla

OBJECTIVES

No routine imaging technology allows reliable visualization of nerve rootlets inside the spinal canal with positive contrast. The stronger MR signal at 7 T, with optimized protocols, may offer a solution. The purpose was to evaluate the potential of 3D Dual-Echo Steady-State (DESS) MR imaging of the cervical spine at 3 and 7 T in assessing the micro-anatomy of the nerve rootlets.

MATERIALS/METHODS

This prospective study was approved by the local ethics committee. Twenty-one patients, clinically referred to cervical-spine MRI, underwent additional MR exams at 3 T and 7 T, each of which consisted of a single 3D-DESS series with equal acquisition times. Artifacts, visualization quality, and number of identified rootlets (C2 to C8) were rated by two musculoskeletal radiologists. Results were compared by Wilcoxon tests. Interobserver reliability was assessed using weighted κ statistics and intraclass correlation coefficient (ICC).

RESULTS

Intraspinal rootlets could successfully be visualized at both field strengths. Rating differences for artifacts and quality of rootlet depiction were not significant for the two field strengths. The mean number of identified rootlets was larger for 7-T than for 3-T MR for every assessed nerve; however, this difference was not statistically significant using the Bonferroni correction (p values ranging from 0.002 to 0.53). Interobserver agreement was substantial to almost perfect (weighted κ values of 0.69 and 0.82). The ICC for the number of identified rootlets was 0.80.

CONCLUSION

Non-invasive 3D-DESS MR-imaging at 3 and 7 T has the potential to provide precise assessments of the micro-anatomy of intraspinal cervical nerve roots.

KEY POINTS

• Cervical rootlets can be successfully visualized with positive contrast using 3D-DESS MR-imaging. • 3D-DESS MR-imaging at 3 and 7 T provides precise assessments of the micro-anatomy of cervical nerves. • The mean number of identified cervical rootlets using 3D-DESS was larger for 7 T than for 3 T MR; however, this difference was not statistically significant.

Diagnostic accuracy of imaging studies for diagnosing root avulsions in post-traumatic upper brachial plexus traction injuries in adults

BACKGROUND

There is no consensus about which type of imaging study, computed tomography myelography (CTM) or magnetic resonance imaging (MRI), provides better information concerning root avulsion in adult brachial plexus injuries.

METHODS

Patients with upper brachial plexus traumatic injuries underwent both CTM and MRI and surgical exploration. The imaging studies were analyzed by two independent radiologists and the data were compared with the intraoperative findings. The statistical analysis was based on dichotomous classification of the nerve roots (normal or altered). The interobserver agreement was assessed using Cohen's Kappa. The accuracy of CTM and MRI in comparison with the intraoperative findings was evaluated using the same methodology.

RESULTS

Fifty-two adult patients were included. CTM tended to yield slightly higher percentages of alterations than MRI The interobserver agreement was better on CTM than on MRI for all nerve roots: C5, 0.9960 (strong) vs. 0.145 (poor); C6, 0.970 (strong) vs. 0.788 (substantial); C7, 0.969 (strong) vs. 0.848 (strong). The accuracy regarding the intraoperative findings was also higher on CTM (moderate, kappa 0.40-0.59) than on MRI (minimal, kappa 0.20-0.39) for all nerve roots. Accordingly, the overall percentage concordance (both normal or both altered) was superior in the CTM evaluation (approx. 70-75% vs. 60-65%). CTM was superior for both sensitivity and specificity at all nerve roots.

CONCLUSION

CTM had greater interobserver agreement and higher diagnostic accuracy than MRI in adult patients with root avulsions due to brachial plexus injury.

Is Pseudomeningocele an Absolute Sign of Root Avulsion Brachial Plexus Injury?

BACKGROUND

The finding of pseudomeningocele from cervical myelogram is widely accepted as a pathognomonic sign for diagnosing root avulsion in brachial plexus injury. In general, motor power in this setting should be absent. However, in clinical practice, we observed that motor power in some patients was still preserved. The objective of this study is to evaluate the accuracy of pseudomeningocele from cervical myelogram for predicting root avulsion in brachial plexus injury.

METHODS

We retrospectively reviewed 201 patients with brachial plexus injury from 2007-2011. Four patients were excluded due to open wound injury. Motor power of the key muscle of each nerve root was evaluated by skilled hand surgeons. All cervical myelogram was interpreted by radiologists. Sensitivities, specificities, positive predictive values and negative predictive values were calculated with 95% confidence interval.

RESULTS

Thirty and 29% of pseudomeningocele occurred at C7 and C8 level, respectively. The sensitivity of pseudomeningocele of each root from C5 to T1 was low (range, 10-62%). The specificity was high only at C5 (91%) and T1 (96.2%). Over 20% of patients with pseudomeningocele at C6-8 levels had some motor function. The initial muscle power of these patients was M1 or M2 and 70% of them recovered to at least M3 at the final follow-up.

CONCLUSIONS

Pseudomeningocele is not an absolute sign for diagnosing of root avulsion in brachial plexus injury due to its high false positive rate when compared with preoperative motor function of each root. Careful examination of the key muscle of each root is extremely crucial to prevent unnecessary operation on that cervical nerve root.

The Use of Dynamic Assist Orthosis for Muscle Reeducation following Brachial Plexus Injury and Reconstruction

Therapeutic management of brachial plexus injuries remains complex. The impact of brachial plexus injuries on everyday human functioning should not be underestimated. Early active-assisted range of motion following such injuries may prevent myostatic contractures, minimize muscle atrophy, facilitate muscle fiber recruitment, and enable a faster return to baseline strength levels. The dynamic assist elbow flexion orthosis proposed is designed to provide patients with a graded system for muscle reeducation and function. No clinical data are currently available on the use of this orthosis design; however, this article presents a treatment option based on sound clinical reasoning to facilitate rehabilitation following this devastating injury.

Standard neurophysiological studies and motor evoked potentials in evaluation of traumatic brachial plexus injuries - A brief review of the literature

PURPOSE

Traumatic damage to the brachial plexus is associated with temporary or permanent motor and sensory dysfunction of the upper extremity. It may lead to the severe disability of the patient, often excluded from the daily life activity. The pathomechanism of brachial plexus injury usually results from damage detected in structures taking origin in the rupture, stretching or cervical roots avulsion from the spinal cord. Often the complexity of traumatic brachial plexus injury requires a multidisciplinary diagnostic process including clinical evaluation supplemented with clinical neurophysiology methods assessing the functional state of its structures. Their presentation is the primary goal of this paper.

METHODS

The basis for the diagnosis of brachial plexus function is a clinical examination and neurophysiology studies: electroneurography (ENG), needle electromyography (EMG), somatosensory evoked potentials (SEPs) and motor evoked potentials (MEPs) assessing the function of individual brachial plexus elements.

CONCLUSIONS

The ENG and EMG studies clarify the level of brachial plexus damage, its type and severity, mainly using the Seddon clinical classification. In contrast to F-wave studies, the use of the MEPs in the evaluation of traumatic brachial plexus injury provides valuable information about the function of its proximal part. MEPs study may be an additional diagnostic in confirming the location and extent of the lesion, considering the pathomechanism of the damage. Clinical neurophysiology studies are the basis for determining the appropriate therapeutic program, including choice of conservative or reconstructive surgery which results are verified in prospective studies.

Pseudomeningocele after traumatic nerve root avulsion. A novel technique to close the fistula

Traumatic brachial plexus complete avulsions and the subsequent formation of pseudomeningoceles are a well-known entity that usually remains asymptomatic. Pseudomeningocele is due to the dural sleeve encasing the damaged roots and the spinal liquid that may accumulate locally or in the supraclavicular soft tissues. The pseudomeningocele, added to the associated lesion of the plexus and usually the surrounding vessels, may become difficult to manage. We describe the novel management of a traumatic pseudomeningocele using an endovascular technique.

Magnetic resonance imaging in brachial plexus injury

Brachial plexus injury represents the most severe nerve injury of the extremities. While obstetric brachial plexus injury has showed a reduction in the number of cases due to the improvements in obstetric care, brachial plexus injury in the adult is an increasingly common clinical problem. The therapeutic measures depend on the pathologic condition and the location of the injury: Preganglionic avulsions are usually not amenable to surgical repair; function of some denervated muscles can be restored with nerve transfers from intercostals or accessory nerves and contralateral C7 transfer. Postganglionic avulsions are repaired with excision of the damaged segment and nerve autograft between nerve ends or followed up conservatively. Magnetic resonance imaging is the modality of choice for depicting the anatomy and pathology of the brachial plexus: It demonstrates the location of the nerve damage (crucial for optimal treatment planning), depicts the nerve continuity (with or without neuroma formation), or may show a completely disrupted/avulsed nerve, thereby aiding in nerve-injury grading for preoperative planning. Computed tomography myelography has the advantage of a higher spatial resolution in demonstration of nerve roots compared with MR myelography; however, it is invasive and shows some difficulties in the depiction of some pseudomeningoceles with little or no communication with the dural sac.

A NIR Dye for Development of Peripheral Nerve Targeted Probes

Current imaging modalities lack the ability to quickly assess and classify nerve injury for predicting favourable versus unfavourable healing outcomes, which could minimize episodes of chronic pain and loss of function by allowing for early intervention. Thus, the development of a technique to noninvasively assess peripheral nerve damage is of critical importance. While the development of nerve specific near infrared (NIR) molecular probes capable of such diagnostics constitutes our long term goal, initial studies to identify a NIR dye for constructing such a probe are required. We have evaluated the properties of a novel highly hydrophilic and functionalizable polymethine dye, and its more hydrophobic analogue indocyanine green, within the sciatic nerve of rats following intra-nerve injection. The reporting ability of both dyes at critical depths for nerve imaging, the importance of hydrophilicity on dye transport through nervous tissue, and their toxicity - or lack thereof - to the neural environment have been evaluated. The results suggest that the novel NIR dye is an appropriate fluorescent reporter for use in designing nerve-specific optical molecular probes for non-invasive diagnosis and classification of nerve injury.

Computer simulation of nerve transfer strategies for restoring shoulder function after adult C5 and C6 root avulsion injuries

PURPOSE

Functional ability after nerve transfer for upper brachial plexus injuries relies on both the function and magnitude of force recovery of targeted muscles. Following nerve transfers targeting either the axillary nerve, suprascapular nerve, or both, it is unclear whether functional ability is restored in the face of limited muscle force recovery.

METHODS

We used a computer model to simulate flexing the elbow while maintaining a functional shoulder posture for 3 nerve transfer scenarios. We assessed the minimum restored force capacity necessary to perform the task, the associated compensations by neighboring muscles, and the effect of altered muscle coordination on movement effort.

RESULTS

The minimum force restored by the axillary, suprascapular, and combined nerve transfers that was required for the model to simulate the desired movement was 25%, 40%, and 15% of the unimpaired muscle force capacity, respectively. When the deltoid was paralyzed, the infraspinatus and subscapularis muscles generated higher shoulder abduction moments to compensate for deltoid weakness. For all scenarios, movement effort increased as restored force capacity decreased.

CONCLUSIONS

Combined axillary and suprascapular nerve transfer required the least restored force capacity to perform the desired elbow flexion task, whereas single suprascapular nerve transfer required the most restored force capacity to perform the same task. Although compensation mechanisms allowed all scenarios to perform the desired movement despite weakened shoulder muscles, compensation increased movement effort. Dynamic simulations allowed independent evaluation of the effect of restored force capacity on functional outcome in a way that is not possible experimentally.

CLINICAL RELEVANCE

Simultaneous nerve transfer to suprascapular and axillary nerves yields the best simulated biomechanical outcome for lower magnitudes of muscle force recovery in this computer model. Axillary nerve transfer performs nearly as well as the combined transfer, whereas suprascapular nerve transfer is more sensitive to the magnitude of reinnervation and is therefore avoided.

MR imaging evaluation of disorders of the chest wall

Chest wall lesions constitute a diverse group of thoracic diseases, including those of soft tissue and osseous origin. MR imaging, with its superior tissue-resolving capability and multiplanar image acquisition, is an important tool for assessing chest wall lesions. In this article, the authors review common and uncommon diseases of the chest wall, with an emphasis on the MR imaging characteristics of these diseases. Among the diseases they discuss are diseases of the soft tissue including lipoma, hibernoma, liposarcoma, hemangioma, and lymphoma. They also examine diseases of the osseous thorax, including benign osseous tumors, fibrous dysplasia, and aneurysmal bone cyst. In addition, they discuss such malignant osseous tumors as osteosarcoma and Ewing's sarcoma.

Management of brachial plexus injuries

Most brachial plexus lesions are traction injuries sustained during birth, but in adolescents and older people they are usually caused by traffic accidents or following a fall in the home. A minority are the result of penetrating injury after civilian assault or trauma encountered during wartime. Birth palsy cases (obstetric brachial plexus palsy) and the remaining cases (traumatic briachial plexus palsy) are viewed differently with regard to treatment and outcome and so these two groups are usually discussed in separate chapters. In this paper we treat both groups in parallel because as far as primary (= nerve) surgery is concerned, many treatment problems and solutions are present in both groups and are therefore comparable.

Diagnostic value and surgical implications of the magnetic resonance imaging in the management of adult patients with brachial plexus pathologies

The imaging of the brachial plexus (BP) cannot easily be achieved because of the extension of the region to be studied, the different tissue compositions of the adjacent anatomic structures and the necessity to work with thin tissue slices. Here is a description of the brachial plexus MRI (bpMRI) protocol that we use for the pre-operative evaluation of patients affected by the following brachial plexus (BP) pathologies: neoplastic, post-traumatic, inflammatory. The surgical implications are discussed. A survey was done on 115 patients (66 males; 49 females; mean age 46.4 years old), which underwent a bpMRI over a 32-month period (32 post-traumatic, 26 neoplastic, 25 affected by inflammatory diseases). Our bpMRI protocol is evaluated according to each mechanism of disease. The bpMRI provides a topographic localization of the tumour showing the nerve dislocations or infiltration by the neoplasm. In traumatic patients we suggest that the bpMRI could be useful to detect the degree of axonal damage when the nerve lesion is in continuity. We also consider the diagnosis and the possible surgical implications for the inflammatory plexopathies. In conclusion, a standardized bpMRI protocol has an invaluable diagnostic value for the surgeons and neurologists. It is only limited by its duration (at least 45 min).

Scapulothoracic dissociation: case report and review of current management

Scapulothoracic dissociation (SD) was first recognized as a distinct traumatic injury pattern in 1984. This case report and review of the literature will be a comprehensive description of this syndrome and its management. Although the extremity prognosis of this injury is poor, patient outcome can be optimized so that the patient can be returned to the best possible functional status in the most expedient manner.

High-resolution ultrasound of the supraclavicular brachial plexus—can it improve therapeutic decisions in patients with plexus trauma?

Patients with major traumatic brachial plexus lesions benefit from early surgery, but they are seldom isolated by today's diagnostic workup. Subjects with ambiguous findings after such workups usually undergo a trial of conservative treatment and those without improvement delayed surgery. Our study focuses on this problem. Hence, the purpose of this study was to evaluate the impact of high-resolution ultrasound (HR-US) on patient recruitment for non-delayed surgery. Twelve patients after blunt shoulder trauma and standardized HR-US assessment who underwent plexus surgery were included in this prospective observational study. Thereby, a total of 168 plexus elements were evaluated. All findings were compared to electrophysiological data if available and tested statistically against the gold-standard, i.e., surgical validation. Major plexus lesions were correctly detected by HR-US in nine patients (20 plexus elements). In two patients (five plexus elements), the lesion was underestimated by HR-US in relation to the gold standard (surgical inspection). Our analysis showed a high positive (1.0) and an acceptable negative predictive value (0.92) for the grading of traumatic plexus lesions with HR-US. Based on HR-US findings alone, 9 of 11 patients with objective major lesions would have undergone early surgery. In conclusion, HR-US proved a valuable tool for the triage of patients with traumatic lesions into surgical and non-surgical candidates.

Brachial Plexus Injury: Clinical Manifestations, Conventional Imaging Findings, and the Latest Imaging Techniques

Brachial plexus injury (BPI) is a severe neurologic injury that causes functional impairment of the affected upper limb. Imaging studies play an essential role in differentiating between preganglionic and postganglionic injuries, a distinction that is crucial for optimal treatment planning. Findings at standard myelography, computed tomographic (CT) myelography, and conventional magnetic resonance (MR) imaging help determine the location and severity of injuries. MR imaging sometimes demonstrates signal intensity changes in the spinal cord, and enhancement of nerve roots and paraspinal muscles at MR imaging indicates the presence of root avulsion injuries. New techniques including MR myelography, diffusion-weighted neurography, and Bezier surface reformation can also be useful in the evaluation and management of BPI. MR myelography with state-of-the-art technology yields remarkably high-quality images, although it cannot replace CT myelography entirely. Diffusion-weighted neurography is a cutting-edge technique for visualizing postganglionic nerve roots. Bezier surface reformation allows the depiction of entire intradural nerve roots on a single image. CT myelography appears to be the preferred initial imaging modality, with standard myelography and contrast material-enhanced MR imaging being recommended as additional studies. Work-up will vary depending on the equipment used, the management policy of peripheral nerve surgeons, and, most important, the individual patient.

Imaging the anatomy of the brachial plexus: review and self-assessment module

OBJECTIVE

The educational objectives of this continuing medical education activity are to describe the normal anatomy of the brachial plexus, to name the most common symptoms associated with a brachial plexopathy, to describe the most common imaging findings resulting from trauma to the brachial plexus, to describe the imaging manifestations of common neoplasias affecting the brachial plexus, and to also describe the imaging findings and symptoms related to irradiation-induced brachial plexopathies.

CONCLUSION

In this article, I have illustrated and described the normal anatomy of the brachial plexus; the most common symptoms related to brachial plexopathy; and imaging findings related to trauma, tumors, and irradiation affecting the brachial plexus.