Resting-state brain network remodeling after different nerve reconstruction surgeries:a functional magnetic resonance imaging study in brachial plexus injury rats

Distinct brain remodeling has been found after different nerve reconstruction strategies,including motor representation of the affected limb.However,differences among reconstruction strategies at the brain network level have not been elucidated.This study aimed to explore intranetwork changes related to altered peripheral neural pathways after different nerve reconstruction surgeries,including nerve repair,endto-end nerve transfer,and end-to-side nerve transfer.Sprague–Dawley rats underwent complete left brachial plexus transection and were divided into four equal groups of eight:no nerve repair,grafted nerve repair,phrenic nerve end-to-end transfer,and end-to-side transfer with a graft sutured to the anterior upper trunk.Resting-state brain functional magnetic resonance imaging was obtained 7 months after surgery.The independent component analysis algorithm was utilized to identify group-level network components of interest and extract resting-state functional connectivity values of each voxel within the component.Alterations in intra-network resting-state functional connectivity were compared among the groups.Target muscle reinnervation was assessed by behavioral observation(elbow flexion)and electromyography.The results showed that alterations in the sensorimotor and interoception networks were mostly related to changes in the peripheral neural pathway.Nerve repair was related to enhanced connectivity within the sensorimotor network,while end-to-side nerve transfer might be more beneficial for restoring control over the affected limb by the original motor representation.The thalamic-cortical pathway was enhanced within the interoception network after nerve repair and end-to-end nerve transfer.Brain areas related to cognition and emotion were enhanced after end-to-side nerve transfer.Our study revealed important brain networks related to different nerve reconstructions.These networks may be potential targets for enhancing motor recovery.

Electroacupuncture attenuates neuropathic pain after brachial plexus injury

Electroacupuncture has traditionally been used to treat pain, but its effect on pain following brachial plexus injury is still unknown. In this study, rat models of an avulsion injury to the left brachial plexus root （associated with upper-limb chronic neuropathic pain） were given electroacupuncture stimulation at bilateral Quchi （LIll）, Hegu （LI04）, Zusanli （ST36） and Yanglingquan （GB34）. After electroacupuncture therapy, chronic neuropathic pain in the rats＇ upper limbs was significantly attenuated. Immunofluorescence staining showed that the expression of β-endorphins in the arcuate nucleus was significantly increased after therapy. Thus, experimental findings indi- cate that electroacupuncture can attenuate neuropathic pain after brachial plexus injury through upregulating β-endorphin expression.

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 em-bryonic 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 C6root 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, 3μL/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 signiifcantly improved at 26 weeks after injury. These data indicate that transplantation of human amniotic epithelial cells can effec-tively 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.

Cell transplantation for the treatment of spinal cord injury–bone marrow stromal cells and choroid plexus epithelial cells

Transplantation of bone marrow stromal cells （BMSCs） enhanced the outgrowth of regenerating axons and promoted locomotor improvements of rats with spinal cord injury （SCI）. BMSCs did not survive long-term, disappearing from the spinal cord within 2-3 weeks after transplantation. Astrocyte-devoid areas, in which no astrocytes or oligodendrocytes were found, formed at the epicenter of the lesion. It was remarkable that numerous regenerating axons extended through such astrocyte-devoid areas. Regenerating axons were associated with Schwann cells embedded in extracellular matrices. Transplantation of choroid plexus epithelial cells （CPECs） also enhanced axonal regeneration and locomotor improvements in rats with SCI. Although CPECs disappeared from the spinal cord shortly after transplantation, an extensive outgrowth of regenerating axons occurred through astrocyte-devoid areas, as in the case of BMSC transplantation. These findings suggest that BMSCs and CPECs secret neurotrophic factors that promote tissue repair of the spinal cord, including axonal regeneration and reduced cavity formation. This means that transplantation of BMSCs and CPECs promotes ＂intrinsic＂ ability of the spinal cord to regenerate. The treatment to stimu- late the intrinsic regeneration ability of the spinal cord is the safest method of clinical application for SCI. It should be emphasized that the generally anticipated long-term survival, proliferation and differentiation of transplanted cells are not necessarily desirable from the clinical point of view of safety.

Small-worldness of brain networks after brachial plexus injury: a resting-state functional magnetic resonance imaging study

Research on brain function after brachial plexus injury focuses on local cortical functional reorganization,and few studies have focused on brain networks after brachial plexus injury.Changes in brain networks may help understanding of brain plasticity at the global level.We hypothesized that topology of the global cerebral resting-state functional network changes after unilateral brachial plexus injury.Thus,in this cross-sectional study,we recruited eight male patients with unilateral brachial plexus injury（right handedness,mean age of 27.9±5.4years old）and eight male healthy controls（right handedness,mean age of 28.6±3.2）.After acquiring and preprocessing resting-state magnetic resonance imaging data,the cerebrum was divided into 90 regions and Pearson’s correlation coefficient calculated between regions.These correlation matrices were then converted into a binary matrix with affixed sparsity values of 0.1–0.46.Under sparsity conditions,both groups satisfied this small-world property.The clustering coefficient was markedly lower,while average shortest path remarkably higher in patients compared with healthy controls.These findings confirm that cerebral functional networks in patients still show smallworld characteristics,which are highly effective in information transmission in the brain,as well as normal controls.Alternatively,varied small-worldness suggests that capacity of information transmission and integration in different brain regions in brachial plexus injury patients is damaged.

Total brachial plexus injury： contralateral C7 root transfer to the lower trunk versus the median nerve

Contralateral C7（cC7） root transfer to the healthy side is the main method for the treatment of brachial plexus root injury. A relatively new modification of this method involves cC7 root transfer to the lower trunk via the prespinal route. In the current study, we examined the effectiveness of this method using electrophysiological and histological analyses. To this end, we used a rat model of total brachial plexus injury, and cC7 root transfer was performed to either the lower trunk via the prespinal route or the median nerve via a subcutaneous tunnel to repair the injury. At 4, 8 and 12 weeks, the grasping test was used to measure the changes in grasp strength of the injured forepaw. Electrophysiological changes were examined in the flexor digitorum superficialis muscle. The change in the wet weight of the forearm flexor was also measured. Atrophy of the flexor digitorum superficialis muscle was assessed by hematoxylin-eosin staining. Toluidine blue staining was used to count the number of myelinated nerve fibers in the injured nerves. Compared with the traditional method, cC7 root transfer to the lower trunk via the prespinal route increased grasp strength of the injured forepaw, increased the compound muscle action potential maximum amplitude, shortened latency, substantially restored tetanic contraction of the forearm flexor muscles, increased the wet weight of the muscle, reduced atrophy of the flexor digitorum superficialis muscle, and increased the number of myelinated nerve fibers. These findings demonstrate that for finger flexion functional recovery in rats with total brachial plexus injury, transfer of the cC7 root to the lower trunk via the prespinal route is more effective than transfer to the median nerve via subcutaneous tunnel.

Effect of lentiviral vector-mediated overexpression of hypoxia-inducible factor 1 alpha delivered by pluronic F-127 hydrogel on brachial plexus avulsion in rats

Brachial plexus avulsion often results in massive motor neuron death and severe functional deficits of target muscles. However, no satisfactory treatment is currently available. Hypoxia-inducible factor 1α is a critical molecule targeting several genes associated with ischemia-hypoxia damage and angiogenesis. In this study, a rat model of brachial plexus avulsion-reimplantation was established, in which C5–7 ventral nerve roots were avulsed and only the C6 root reimplanted. Different implants were immediately injected using a microsyringe into the avulsion-reimplantation site of the C6 root post-brachial plexus avulsion. Rats were randomly divided into five groups: phosphate-buffered saline, negative control of lentivirus, hypoxia-inducible factor 1α(hypoxia-inducible factor 1α overexpression lentivirus), gel(pluronic F-127 hydrogel), and gel + hypoxia-inducible factor 1α(pluronic F-127 hydrogel + hypoxia-inducible factor 1α overexpression lentivirus). The Terzis grooming test was performed to assess recovery of motor function. Scores were higher in the hypoxia-inducible factor 1α and gel +hypoxia-inducible factor 1α groups(in particular the gel + hypoxia-inducible factor 1α group) compared with the phosphate-buffered saline group. Electrophysiology, fluorogold retrograde tracing, and immunofluorescent staining were further performed to investigate neural pathway reconstruction and changes of neurons, motor endplates, and angiogenesis. Compared with the phosphate-buffered saline group, action potential latency of musculocutaneous nerves was markedly shortened in the hypoxia-inducible factor 1α and gel + hypoxia-inducible factor1α groups. Meanwhile, the number of fluorogold-positive cells and ChAT-positive neurons, neovascular area(labeled by CD31 around av ulsed sites in ipsilateral spinal cord segments), and the number of motor endplates in biceps brachii(identified by α-bungarotoxin) were all visibly increased, as well as the morphology of motor endplate in biceps brachil was clear in the hypoxia-inducible factor 1α and gel + hypoxia-inducible factor 1α groups. Taken together, delivery of hypoxia-inducible factor 1α overexpression lentiviral vectors mediated by pluronic F-127 effectively promotes spinal root regeneration and functional recovery post-brachial plexus avulsion. All animal procedures were approved by the Institutional Animal Care and Use Committee of Guangdong Medical University, China.

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.

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.

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.

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 per-formed 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 conduc-tion 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 regener-ated potentials ifrst 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 ‘ex-cellent’ 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 func-tional recovery of a transplanted nerve can be dynamically observed after the surgery.

Valproic acid protects neurons and promotes neuronal regeneration after brachial plexus avulsion

Valproic acid has been shown to exert neuroprotective effects and promote neurite outgrowth in several peripheral nerve injury models. However, whether valproic acid can exert its beneficial effect on neurons after brachial plexus avulsion injury is currently unknown. In this study, brachial plexus root avulsion models, established in Wistar rats, were administered daily with valproic acid dis-solved in drinking water （300 mg/kg） or normal water. On days 1, 2, 3, 7, 14 and 28 after avulsion injury, tissues of the C 5-T 1 spinal cord segments of the avulsion injured side were harvested to in-vestigate the expression of Bcl-2, c-Jun and growth associated protein 43 by real-time PCR and western blot assay. Results showed that valproic acid significantly increased the expression of Bcl-2 and growth associated protein 43, and reduced the c-Jun expression after brachial plexus avulsion. Our findings indicate that valproic acid can protect neurons in the spinal cord and enhance neuronal regeneration fol owing brachial plexus root avulsion.

Effects of brachial plexus injury anastomosis simulation on biomechanical properties of adult brachial plexus

BACKGROUND： Previous studies of peripheral nerve mechanical properties in animals have utilized one-dimensional drawing methods. OBJECTIVE： To analyze the effects of brachial plexus injury anastomosis simulation on biomechanical properties of adult brachial plexus by observing tensile mechanical properties, stress relaxation, and creep deformation of the brachial plexus in normal human cadavers and brachial plexus from simulated brachial plexus injury anastomosis samples. DESIGN, TIME AND SETTING： The in vitro experiment was performed at the Mechanics Experimental Center, Jilin University, China from April to May 2007. MATERIALS： A total of six adult, male cadavers, who had died from acute trauma, and were aged 20-29 years, were supplied by the Research Room of Anatomy, Medical Department, Jilin University, China. AG-10TA Universal Material Testing Machine （Shimadzu, Japan） was used in this study. METHODS： A total of 36 samples of fresh brachial plexus were collected from the cadavers, comprising 12 C5 nerve roots, 12 C6 nerve roots at the left and right sides of the superior truck, and 12 C7 nerve roots at the middle truck. The C5 and C6 nerve roots were processed into 50 samples and the C7 nerve roots into 24 samples. A total of 36 C5 and C6 nerve root samples were randomly assigned to a non-surgery control group （n = 18） and brachial plexus injury anastomosis simulation group （n = 18）. Brachial plexus injury simulation anastomosis samples underwent an incision in the middle, and then received anastomosis. Samples in both groups underwent a tension test at 5 mm/min on the AG-10TA universal material testing machine. A total of 24 samples from the C6 superior trunk and C7 middle trunk of the brachial plexus were subjected to stress relaxation and creep tests. Test duration was 7 200 seconds. A total of 100 data points were collected and analyzed using a normalization method. MAIN OUTCOME MEASURES： The following parameters were measured： tension maximum displacement, maximum load, maximum stress, maximum strain and stress-strain curve, stress relaxation at 7 200 seconds, creep deformation at 7 200 seconds, stress relaxation, and creep curve in the non-surgery control group and brachial plexus injury simulation anastomosis group. RESULTS： The tension maximum load of brachial plexus was （140.36 ± 30.50） N, maximum stress was （10.67 ± 2.52） MPa, maximum displacement was （7.78 ± 1.48） mm, and maximum strain was （31.64 ± 5.32）% in the non-surgery control group. The tension maximum load of brachial plexus was （93.23 ± 20.65） N, maximum stress was （7.09 ± 1.57） MPa, maximum displacement was （6.13 ± 0.86） mm,and maximum strain was （24.55 ± 3.45）% in the brachial plexus injury simulation anastomosis group. The above-mentioned indices were greater in the non-surgery control group than in the brachial plexus injury simulation anastomosis group （P 〈 0.01）. Stress relaxation at 7 200 seconds was 2.07 MPa and 2.11 MPa, respectively, in the non-surgery control and brachial plexus injury simulation anastomosis groups. Creep deformation at 7 200 seconds was 4.68% and 3.52%, respectively, in the non-surgery control and brachial plexus injury simulation anastomosis groups. CONCLUSION： Decreased tension maximum load, maximum displacement, maximum stress, maximum strain, and creep deformation at 7 200 seconds affected the biomechanical properties of the brachial plexus following brachial plexus injury.

Restoration and protection of brachial plexus injury: hot topics in the last decade

Brachial plexus injury is frequently induced by injuries, accidents or birth trauma. Upper limb function may be partially or totally lost after injury, or left permanently disabled. With the de- velopment of various medical technologies, different types of interventions are used, but their effectiveness is wide ranging. Many repair methods have phasic characteristics, i.e., repairs are done in different phases. This study explored research progress and hot topic methods for pro- tection after brachial plexus injury, by analyzing 1,797 articles concerning the repair of brachial plexus injuries, published between 2004 and 2013 and indexed by the Science Citation Index database. Results revealed that there are many methods used to repair brachial plexus injury, and their effects are varied. Intervention methods include nerve transfer surgery, electrical stimula- tion, cell transplantation, neurotrophic factor therapy and drug treatment. Therapeutic methods in this field change according to the hot topic of research.

Brachial Plexus Neuropraxia after CT-Guided Radiofrequency Ablation in a Patient with a Narrow Costoclavicular Space: A Case Report

A case of brachial plexus neuropraxia occurring during CT-guided radiofrequency ablation is reported in a patient with a narrow costoclavicular space. We discuss clinical methods of identifying patients with a narrow costoclavicular space who are at risk of position-related injury of the brachial plexus during anaesthesia. Identifying high risk patients and proper positioning during anaesthesia are hallmarks of preventing such injuries.

Stability of motor endplates is greater in the biceps than in the interossei in a rat model of obstetric brachial plexus palsy

The time window for repair of the lower trunk is shorter than that of the upper trunk in patients with obstetric brachial plexus palsy. The denervated intrinsic muscles of the hand become irreversibly atrophic much faster than the denervated biceps. However, it is unclear whether the motor endplates of the denervated interosseous muscles degenerate more rapidly than those of the denervated biceps. In this study, we used a rat model of obstetric brachial plexus palsy of the right upper limb. C5–6 was lacerated distal to the intervertebral foramina, with concurrent avulsion of C7–8 and T1, with the left upper limb used as the control. Bilateral interossei and biceps were collected at 5 and 7 weeks. Immunofluorescence was used to assess the morphology of the motor endplates. Real-time quantitative polymerase chain reaction and western blot assay were used to assess mRNA and protein expression levels of acetylcholine receptor subunits(α, β and δ), rapsyn and β-catenin. Immunofluorescence microscopy showed that motor endplates in the denervated interossei were fragmented, while those in the denervated biceps were morphologically intact with little fragmentation. The number and area of motor endplates, relative to the control side, were significantly lower in the denervated interossei compared with the denervated biceps. mRNA and protein expression levels of acetylcholine receptor subunits(α, β and δ) were significantly lower, whereas β-catenin protein expression was higher, in the denervated interossei compared with the denervated biceps. The protein expression of rapsyn was higher in the denervated biceps than in the denervated interossei at 7 weeks. Our findings demonstrate that motor endplates of interossei are destabilized, whereas those of the biceps remain stable, in the rat model of obstetric brachial plexus palsy. All procedures were approved by the Experimental Animal Ethics Committee of Fudan University, China(approval No. DF-187) in January 2016.

Motor neuron-specific RhoA knockout delays degeneration and promotes regeneration of dendrites in spinal ventral horn after brachial plexus injury

Dendrites play irreplaceable roles in the nerve conduction pathway and are vulnerable to various insults.Peripheral axotomy of motor neurons results in the retraction of dendritic arbors,and the dendritic arbor can be re-expanded when reinnervation is allowed.RhoA is a target that regulates the cytoskeleton and promotes neuronal survival and axon regeneration.However,the role of RhoA in dendrite degeneration and regeneration is unknown.In this study,we explored the potential role of RhoA in dendrites.A line of motor neuronal conditional knockout mice was developed by crossbreeding HB9~(Cre+)mice with RhoA~(flox/flox)mice.We established two models for assaying dendrite degeneration and regeneration,in which the brachial plexus was transection or crush injured,respectively.We found that at 28 days after brachial plexus transection,the density,complexity,and structural integrity of dendrites in the ventral horn of the spinal cord of RhoA conditional knockout mice were slightly decreased compared with that in Cre mice.Dendrites underwent degeneration at 7 and 14 days after brachial plexus transection and recovered at 28–56 days.The density,complexity,and structural integrity of dendrites in the ventral horn of the spinal cord of RhoA conditional knockout mice recovered compared with results in Cre mice.These findings suggest that RhoA knockout in motor neurons attenuates dendrite degeneration and promotes dendrite regeneration after peripheral nerve injury.

Prevention of shoulder dystocia related birth injuries: Myths and facts

Traditionally, brachial plexus damage was attributed to excessive traction applied on the fetal head at delivery. Recently, it was proposed that most injuries occur spontaneously in utero. The author has studied the mechanism of neurological birth injuries based on 338 actual cases with special attention to(1) fetal macrosomia;(2) maternal diabetes; and(3) methods of delivery. There was a high coincidence between use of traction and brachial plexus injuries. Instrumental extractions increased the risk exponentially. Erb's palsy following cesarean section was exceedingly rare. These facts imply that spontaneous neurological injury in utero is extremely rare phenomenon. Literary reports show that shoulder dystocia and its associated injuries increased in the United States several-fold since the introduction of active management of delivery in the 1970's. Such a dramatic change in a stable population is unlikely to be caused by incidental spontaneous events unrelated to external factors. The cited investigations indicate that brachial plexus damage typically is traction related. The traditional technique which precludes traction is the optimal method for avoiding arrest of the shoulders and its associated neurological birth injuries. Effective prevention also requires meticulous prenatal care and elective abdominal delivery of macrosomic fetuses in carefully selected cases.

Improved C_(3-4) 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 C34 transfer for neurotization of 05-6. 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 IIHV, scapular muscle to level Ill-W, latissimus dorsi and pectoralis major muscles to above level Ⅲ, and the brachial triceps muscle to level 0 Ill. Results showed that the improved 03-4 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.

3.0-T magnetic resonance imaging in children with brachial plexus birth injury

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.