Phrenic nerve transfer to the musculocutaneous nerve for the repair of brachial plexus injury: electrophysiological characteristics

Phrenic nerve transfer is a major dynamic treatment used to repair brachial plexus root avulsion. We analyzed 72 relevant articles on phrenic nerve transfer to repair injured brachial plexus that were indexed by Science Citation Index. The keywords searched were brachial plexus injury, phrenic nerve, repair, surgery, protection, nerve transfer, and nerve graft. In addition, we performed neurophysiological analysis of the preoperative condition and prognosis of 10 patients undergoing ipsilateral phrenic nerve transfer to the musculocutaneous nerve in our hospital from 2008 to 201 3 and observed the electromyograms of the biceps brachii and motor conduction function of the musculocutaneous nerve. Clinically, approximately 28% of patients had brachial plexus injury combined with phrenic nerve injury, and injured phrenic nerve cannot be used as a nerve graft. After phrenic nerve transfer to the musculocutaneous nerve, the regenerated potentials first appeared at 3 months. Recovery of motor unit action potential occurred 6 months later and became more apparent at 12 months. The percent of patients recovering ‘excellent' and ‘good' muscle strength in the biceps brachii was 80% after 18 months. At 12 months after surgery, motor nerve conduction potential appeared in the musculocutaneous nerve in seven cases. These data suggest that preoperative evaluation of phrenic nerve function may help identify the most appropriate nerve graft in patients with an injured brachial plexus. The functional recovery of a transplanted nerve can be dynamically observed after the surgery.     

Improved C3-4 transfer for treatment of root avulsion of the brachial plexus upper trunk Animal experiments and clinical application

Experimental rats with root avulsion of the brachial plexus upper trunk were treated with the improved C3-4 transfer for neurotization of C5-6.Results showed that Terzis grooming test scores were significantly increased at 6 months after treatment,the latency of C5-6 motor evoked potential was gradually shortened,and the amplitude was gradually increased.The rate of C3 instead of C5 and the C4 + phrenic nerve instead of C6 myelinated nerve fibers crossing through the anastomotic stoma was approximately 80%.Myelinated nerve fibers were arranged loosely but the thickness of the myelin sheath was similar to that of the healthy side.In clinical applications,39 patients with root avulsion of the brachial plexus upper trunk were followed for 6 months to 4.5 years after treatment using the improved C3 instead of C5 nerve root transfer and C4 nerve root and phrenic nerve instead of C6 nerve root transfer.Results showed that the strength of the brachial biceps and deltoid muscles recovered to level III-IV,scapular muscle to level III-IV,latissimus dorsi and pectoralis major muscles to above level III,and the brachial triceps muscle to level 0-III.Results showed that the improved C3-4 transfer for root avulsion of the brachial plexus upper trunk in animal models is similar to clinical findings and that C3-4 and the phrenic nerve transfer for neurotization of C5-6 can innervate the avulsed brachial plexus upper trunk and promote the recovery of nerve function in the upper extremity.     

Supplementary motor area deactivation impacts the recovery of hand function from severe peripheral nerve injury

Although some patients have successful peripheral nerve regeneration, a poor recovery of hand function often occurs after peripheral nerve injury. It is believed that the capability of brain plasticity is crucial for the recovery of hand function. The supplementary motor area may play a key role in brain remodeling after peripheral nerve injury. In this study, we explored the activation mode of the supplementary motor area during a motor imagery task. We investigated the plasticity of the central nervous system after brachial plexus injury, using the motor imagery task. Results from functional magnetic resonance imaging showed that after brachial plexus injury, the motor imagery task for the affected limbs of the patients triggered no obvious activation of bilateral supplementary motor areas. This result indicates that it is dififcult to excite the supplementary motor areas of brachial plexus injury patients during a motor imagery task, thereby impacting brain remodeling. Deactivation of the supplementary motor area is likely to be a serious problem for brachial plexus injury patients in terms of preparing, initiating and executing certain movements, which may be partly responsible for the unsatisfactory clinical recovery of hand function.     

Structure of the brachial plexus root and adjacent regions displayed by ultrasound imaging

Brachial plexuses of 110 healthy volunteers were examined using high resolution color Doppler ultrasound. Ultrasonic characteristics and anatomic variation in the intervertebral foramen, interscalene, supraclavicular and infraclavicular, as well as the axillary brachial plexus were investigated. Results confirmed that the normal brachial plexus on cross section exhibited round or elliptic hypoechoic texture. Longitudinal section imaging showed many parallel linear hypo-moderate echoes, with hypo-echo. The transverse processes of the seventh cervical vertebra, the scalene space, the subclavian artery and the deep cervical artery are important markers in an examination. The display rates for the interscalene, and supraclavicular and axillary brachial plexuses were 100% each, while that for the infraclavicular brachial plexus was 97%. The region where the normal brachial plexus root traversed the intervertebral foramen exhibited a regular hypo-echo. The display rate for the C 5-7 nerve roots was 100%, while those for C 8 and T 1 were 83% and 68%, respectively. A total of 20 of the 110 subjects underwent cervical CT scan. High-frequency ultrasound can clearly display the outline of the transverse processes of the vertebrae, which were consistent with CT results. These results indicate that high-frequency ultrasound provides a new method for observing the morphology of the brachial plexus. The C 7 vertebra is a marker for identifying the position of brachial plexus nerve roots.     

Contralateral C7 transfer combined with acellular nerve allografts seeded with differentiated adipose stem cells for repairing upper brachial plexus injury in rats

Nerve grafting has always been necessary when the contralateral C7 nerve root is transferred to treat brachial plexus injury. Acellular nerve allograft is a promising alternative for the treatment of nerve defects, and results were improved by grafts laden with differentiated adipose stem cells. However, use of these tissue-engineered nerve grafts has not been reported for the treatment of brachial plexus injury. The aim of the present study was to evaluate the outcome of acellular nerve allografts seeded with differentiated adipose stem cells to improve nerve regeneration in a rat model in which the contralateral C7 nerve was transferred to repair an upper brachial plexus injury. Differentiated adipose stem cells were obtained from Sprague-Dawley rats and transdifferentiated into a Schwann cell-like phenotype. Acellular nerve allografts were prepared from 15-mm bilateral sections of rat sciatic nerves. Rats were randomly divided into three groups: acellular nerve allograft, acellular nerve allograft + differentiated adipose stem cells, and autograft. The upper brachial plexus injury model was established by traction applied away from the intervertebral foramen with micro-hemostat forceps. Acellular nerve allografts with or without seeded cells were used to bridge the gap between the contralateral C7 nerve root and C5–6 nerve. Histological staining, electrophysiology, and neurological function tests were used to evaluate the effect of nerve repair 16 weeks after surgery. Results showed that the onset of discernible functional recovery occurred earlier in the autograft group first, followed by the acellular nerve allograft + differentiated adipose stem cells group, and then the acellular nerve allograft group; moreover, there was a significant difference between autograft and acellular nerve allograft groups. Compared with the acellular nerve allograft group, compound muscle action potential, motor conduction velocity, positivity for neurofilament and S100, diameter of regenerating axons, myelin sheath thickness, and density of myelinated fibers were remarkably increased in autograft and acellular nerve allograft + differentiated adipose stem cells groups. These findings confirm that acellular nerve allografts seeded with differentiated adipose stem cells effectively promoted nerve repair after brachial plexus injuries, and the effect was better than that of acellular nerve repair alone. This study was approved by the Animal Ethics Committee of the First Affiliated Hospital of Sun Yat-sen University of China(approval No. 2016-150) in June 2016.     

Functional reconstruction following brachial plexus root avulsion

OBJECTIVE: To sum up the treatment of brachial plexus root avulsion and the progress in functional reconstruction and rehabilitation following brachial plexus root avulsion. DATA SOURCES: A search of Medline was performed to select functional reconstruction and rehabilitation following brachial plexus injury-related English articles published between January 1990 and July 2006, with key words of "brachial plexus injury, reconstruction and rehabilitation". Meanwhile, a computer-based search of CBM was carried out to select the similar Chinese articles published between January 1998 and July 2006, with key words of "brachial plexus injury, reconstruction and rehabilitation". STUDY SELECTION: The materials were checked primarily, and the literatures of functional reconstruction and rehabilitation of brachial plexus injury were selected and the full texts were retrieved. Inclusive criteria: ① Functional reconstruction following brachial plexus injury. ② Rehabilitation method of brachial plexus injury. Exclusive criteria: Reviews, repetitive study, and Meta analytical papers. DATA EXTRACTION: Forty-six literatures about functional reconstruction following brachial plexus injury were collected, and 36 of them met the inclusive criteria. DATA SYNTHESIS: Brachial plexus injury causes the complete or incomplete palsy of muscle of upper extremity. The treatment of brachial plexus is to displace not very important nerves to the distal end of very important nerve, called nerve transfer, which is an important method to treat brachial plexus injury. Postoperative rehabilitations consist of sensory training and motor functional training. It is very important to keep the initiativeness of exercise. Besides recovering peripheral nerve continuity by operation, combined treatment and accelerating neural regeneration, active motors of cerebral cortex is also the important factor to reconstruct peripheral nerve function. CONCLUSION: Consciously and actively strengthening functional exercise after operation is helpful to form cerebral plasticity and produce voluntary movements, can re-educate re-dominated muscle, obviously improves postoperative therapeutic effect and promote functional reconstruction.     

Human amniotic epithelial cell transplantation for the repair of injured brachial plexus nerve: evaluation of nerve viscoelastic properties

The transplantation of embryonic stem cells can effectively improve the creeping strength of nerves near an injury site in animals. Amniotic epithelial cells have similar biological properties as embryonic stem cells; therefore, we hypothesized that transplantation of amniotic epithelial cells can repair peripheral nerve injury and recover the creeping strength of the brachial plexus nerve. In the present study, a brachial plexus injury model was established in rabbits using the C6 root avulsion method. A suspension of human amniotic epithelial cells was repeatedly injected over an area 4.0 mm lateral to the cephal and caudal ends of the C6 brachial plexus injury site(1 × 106 cells/mL, 3 μL/injection, 25 injections) immediately after the injury. The results showed that the decrease in stress and increase in strain at 7,200 seconds in the injured rabbit C6 brachial plexus nerve were mitigated by the cell transplantation, restoring the viscoelastic stress relaxation and creep properties of the brachial plexus nerve. The forepaw functions were also significantly improved at 26 weeks after injury. These data indicate that transplantation of human amniotic epithelial cells can effectively restore the mechanical properties of the brachial plexus nerve after injury in rabbits and that viscoelasticity may be an important index for the evaluation of brachial plexus injury in animals.     

Melatonin combined with chondroitin sulfate ABC promotes nerve regeneration after root-avulsion brachial plexus injury

After nerve-root avulsion injury of the brachial plexus, oxidative damage, inflammatory reaction, and glial scar formation can affect nerve regeneration and functional recovery. Melatonin(MT) has been shown to have good anti-inflammatory, antioxidant, and neuroprotective effects. Chondroitin sulfate ABC(ChABC) has been shown to metabolize chondroitin sulfate proteoglycans and can reduce colloidal scar formation. However, the effect of any of these drugs alone in the recovery of nerve function after injury is not completely satisfactory. Therefore, this experiment aimed to explore the effect and mechanism of combined application of melatonin and chondroitin sulfate ABC on nerve regeneration and functional recovery after nerve-root avulsion of the brachial plexus. Fifty-two Sprague-Dawley rats were selected and their C5–7 nerve roots were avulsed. Then, the C6 nerve roots were replanted to construct the brachial plexus nerve-root avulsion model. After successful modeling, the injured rats were randomly divided into four groups. The first group(injury) did not receive any drug treatment, but was treated with a pure gel-sponge carrier nerve-root implantation and an ethanol-saline solution via intraperitoneal(i.p.) injection. The second group(melatonin) was treated with melatonin via i.p. injection. The third group(chondroitin sulfate ABC) was treated with chondroitin sulfate ABC through local administration. The fourth group(melatonin + chondroitin sulfate ABC) was treated with melatonin through i.p. injection and chondroitin sulfate ABC through local administration. The upper limb Terzis grooming test was used 2–6 weeks after injury to evaluate motor function. Inflammation and oxidative damage within 24 hours of injury were evaluated by spectrophotometry. Immunofluorescence and neuroelectrophysiology were used to evaluate glial scar, neuronal protection, and nerve regeneration. The results showed that the Terzis grooming-test scores of the three groups that received treatment were better than those of the injury only group. Additionally, these three groups showed lower levels of C5–7 intramedullary peroxidase and malondialdehyde. Further, glial scar tissue in the C6 spinal segment was smaller and the number of motor neurons was greater. The endplate area of the biceps muscle was larger and the structure was clear. The latency of the compound potential of the myocutaneous nerve-biceps muscle was shorter. All these indexes were even greater in the melatonin + chondroitin sulfate ABC group than in the melatonin only or chondroitin sulfate ABC only groups. Thus, the results showed that melatonin combined with chondroitin sulfate ABC can promote nerve regeneration after nerve-root avulsion injury of the brachial plexus, which may be achieved by reducing oxidative damage and inflammatory reaction in the injury area and inhibiting glial scar formation.     

Nerve transfer helps repair brachial plexus injury by increasing cerebral cortical plasticity

In the treatment of brachial plexus injury, nerves that are functionally less important are transferred onto the distal ends of damaged crucial nerves to help recover neuromuscular function in the target region. For example, intercostal nerves are transferred onto axillary nerves, and accessory nerves are transferred onto suprascapular nerves, the phrenic nerve is transferred onto the musculocutaneous nerves, and the contralateral C7 nerve is transferred onto the median or radial nerves. Nerve transfer has become a major method for reconstructing the brachial plexus after avulsion injury. Many experiments have shown that nerve transfers for treatment of brachial plexus injury can help reconstruct cerebral cortical function and increase cortical plasticity. In this review article, we summarize the recent progress in the use of diverse nerve transfer methods for the repair of brachial plexus injury, and we discuss the impact of nerve transfer on cerebral cortical plasticity after brachial plexus injury.     

Transplantation of human amniotic epithelial cells repairs brachial plexus injury： pathological and biomechanical analyses

A brachial plexus injury model was established in rabbits by stretching the C6 nerve root. Imme- diately after the stretching, a suspension of human amniotic epithelial cells was injected into the injured brachial plexus. The results of tensile mechanical testing of the brachial plexus showed that the tensile elastic limit strain, elastic limit stress, maximum stress, and maximum strain of the injured brachial plexuses were significantly increased at 24 weeks after the injection. The treatment clearly improved the pathological morphology of the injured brachial plexus nerve, as seen by hematoxylin eosin staining, and the functions of the rabbit forepaw were restored. These data indicate that the injection of human amniotic epithelial cells contributed to the repair of brachial plexus injury, and that this technique may transform into current clinical treatment strategies.     

3.0-T磁共振成像在儿童臂丛神经分娩损伤的作用

Brachial plexus birth injuries in children are usually diagnosed using 1.5-T magnetic resonance imaging,while the application of high-field magnetic resonance imaging is rarely reported.Therefore,a retrospective comparison of 18 cases of children with brachial plexus injury was performed to investigate the characteristics of 3.0-T magnetic resonance imaging and intraoperative observations.Magnetic resonance examinations in 18 cases of children showed that pseudo-meningocele sensitivity,specificity,accuracy,and positivity rates were 83.3%,79.6%,81.1%,and 40.0%,respectively.As for the neuroma and fibrous scar encapsulation,the sensitivity,specificity,accuracy,and positivity rates were 92.9%,50.0%,83.3%,and 77.8%,respectively.These results confirm that 3.0-T high-field magnetic resonance imaging can clearly reveal abnormal changes in brachial plexus injury,in which pseudo-meningocele,fibrous scar encapsulation,and neuroma are the characteristic changes of obstetric brachial plexus preganglionic and postganglionic nerve injury.     

Comparison of the results of surgical treatment after direct neurorrhaphy and reconstruction with sural nerve grafts in perinatal brachial plexus lesions

The neurotmesis of elements of the brachial plexus in perinatal lesions requires microsurgical reconstruction. In this study we present our own experiences in surgical treatment of postganglionic lesions in the fifth degree of injury in Sunderland's scale. The clinical material consisted of 14 children aged from 2.5 to 6 months treated surgically due to neurotmesis of the neural elements of the brachial plexus. In 8 cases direct neurorrhaphy and in 6 cases reconstruction with sural nerve grafts were performed. During the operations material from the proximal stumps of the brachial plexus trunks was collected for histopathological examination. The analysis of the material comprised: clinical type of injury, location of postganglionic lesion and type of surgical procedure. The results of surgical treatment were evaluated using generally accepted scales (Gilbert's, Raimondi's, Al-Qattan's and British Medical Research Council scales). Comparison of the results of treatment between the surgical methods was also performed. Better results of surgical treatment were observed after direct neurorrhaphy. In our opinion the indications for these two methods are different and both operative techniques are useful in surgical treatment of perinatal brachial plexus palsy.     

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.

     

Vertebral-basilar posterior cerebral territory stroke--delineation by proton nuclear magnetic resonance imaging

We used three-dimensional proton NMR images to study ischemic infarction in the territory of the vertebral-basilar posterior cerebral circulation. The study includes sixteen cases, eight of which are presented in detail. In seven cases, the infarctions were secondary to demonstrable large artery occlusive disease -- vertebral, basilar, or posterior cerebral. In nine cases, the infarctions were secondary to what was presumably small vessel disease. In fifteen of the sixteen cases, NMR imaging could locate the infarct, inversion recovery and spin-echo pulse sequences being more sensitive than the saturation recovery pulse sequence. This efficiency rests on the high sensitivity of ischemic infarction to changes in T1 and T2 relaxation time, highlighted in the inversion recovery and spin-echo images, respectively. The additional advantages of the three-dimensional approach, and the lack of bone artifact, make NMR imaging superior to CT scanning in identifying areas of infarction in the territory of posterior cerebral circulation.     

The brachial plexus: normal anatomy, pathology, and MR imaging

The brachial plexus is the most technically and anatomically challenging area of the peripheral nervous system for diagnostic imaging. Marked improvements in spatial and contrast resolution of plexus images have resulted from the use of phased-array technology and newer MR pulse sequence designs. This article presents case material incorporating these improvements and discusses the primary factors that continue to limit MR image quality, such as inhomogenous fat suppression, motion artifacts, and small vessels that mimic or obscure plexus components, and potential solutions and imaging alternatives. Brachial plexus anatomy and its appearance on multiplanar MR images are reviewed. The morphologic features and MR signal characteristics that have been found useful in distinguishing between normal and abnormal plexus components,and in detecting neuropathic lesions, are addressed in the context of clinical indications for plexus imaging as follows: mass involving the plexus, traumatic injury, entrapment syndrome, posttreatment evaluation, and miscellaneous conditions.     

MRI of the brachial plexus

Magnetic resonance imaging is the method of choice for the evaluation of brachial plexopathy. Knowledge of the anatomy and normal imaging appearance is required. High-resolution imaging technique is necessary with the use of adequate coils. Evaluation of the brachial plexus requires T1 weighted sequences in three plans, T2 weighted sequences with fat suppression and if necessary the study is completed with gadolinium injection sequences with fat suppression. A CISS sequence is used if a nerve root avulsion is suspected. The spatial resolution must be optimized with the use of adapted parameters. We illustrate a variety of pathologies that can involve the brachial plexus. The pathology includes trauma, primary (neurogenic tumors, lymphomatosis) or secondary tumors, radiation plexopathy or inflammatory polyneuropathy.     

磁共振神经成像序列在臂丛神经损伤中的应用

目的探讨磁共振神经成像(MRN)序列对臂丛神经损伤的诊断价值。方法采用3.0T MRI对43例临床诊断为臂丛神经损伤患者行术前常规MRI及MRN序列扫描,对手术探查、术中肌电图及术前MRI/MRN检查结果进行比较分析。结果 MRN对节前神经损伤诊断的敏感度为76.2%,特异度为83.6%,准确率为80.0%。MRN对臂丛神经节后损伤诊断的敏感度为74.8%,特异度为88.1%,准确率为79.2%。结论 MRN可作为早期臂丛神经损伤定性及定位诊断的影像学检查方法之一。     

Clinical findings, electroneuromyography and MRI in trauma of the brachial plexus

OBJECTIVES: Management of traumatic lesions of the brachial plexus mainly depends on whether the injury is pre- (nerve root avulsion) or postganglionic (trunks and cords). The aim of this study was to assess the diagnostic and prognostic value of MRI in such lesions, and to determine any correlations among radiological, clinical and electroneuromyographical (EMG) data from both the initial and follow-up studies. MATERIAL AND METHODS: Nine patients with acute traumatic lesions of the brachial plexus were investigated by MRI and EMG. Five further patients served as controls. The MRI protocol included fast spin-echo (FSE) T2-weighted and STIR sequencing. These scans were independently interpreted by two senior radiologists. Their findings were then validated during consensus meetings of surgeons, radiologists and neurologists to identify the exact localization and mechanism of each lesion, and to determine the advantages and drawbacks of each technique. RESULTS: Among the nine patients, MRI scans were judged as normal in three whereas EMG showed distal lesions in two of them. In a further three patients, STIR MRI sequences demonstrated high signal intensities from the trunks and cords of C5 to T1. Among these three patients, MRI at three months showed persistence of these signal anomalies in one patient, and partial regression in the two others. In the remaining three patients, three-dimensional T2-weighted sequences showed nerve root avulsion, consistent with the initial EMG findings. CONCLUSION: MRI is the best technique to demonstrate nerve root avulsion. However, unlike EMG, MRI does not allow visualization of distal lesions of the brachial plexus. Differentiation between edema (reversible) and demyelination (irreversible) of trunk and cord lesions remains difficult, and requires EMG or late MRI.