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.

Evaluation of nerve transfer options for treating total brachial plexus avulsion injury： a retrospective study of 73 participants

Despite recent great progress in diagnosis and microsurgical repair, the prognosis in total brachial plexus-avulsion injury remains unfavorable.Insufficient number of donors and unreasonable use of donor nerves might be key factors. To identify an optimal treatment strategy for this condition, we conducted a retrospective review. Seventy-three patients with total brachial plexus avulsion injury were followed up for an average of 7.3 years. Our analysis demonstrated no significant difference in elbow-flexion recovery between phrenic nerve-transfer （25 cases）, phrenic nerve-graft （19 cases）, intercostal nerve （17 cases）, or contralateral C7-transfer （12 cases） groups. Restoration of shoulder function was attempted through anterior accessory nerve （27 cases）, posterior accessory nerve （10 cases）, intercostal nerve （5 cases）, or accessory ＋ intercostal nerve transfer （31 cases）. Accessory nerve ＋ intercostal nerve transfer was the most effective method. A significantly greater amount of elbow extension was observed in patients with intercostal nerve transfer （25 cases） than in those with contralateral C7 transfer （10 cases）. Recovery of median nerve function was noticeably better for those who received entire contralateral C7 transfer （33 cases） than for those who received partial contralateral C7 transfer （40 cases）. Wrist and finger extension were reconstructed by intercostal nerve transfer （31 cases）. Overall, the recommended surgical treatment for total brachial plexus-avulsion injury is phrenic nerve transfer for elbow flexion, accessory nerve ＋ intercostal nerve transfer for shoulder function, intercostal nerves transfer for elbow extension, entire contralateral C7 transfer for median nerve function, and intercostal nerve transfer for finger extension. The trial was registered at Clinical-Trials.gov （identifier： NCT03166033）.

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.

Differentiation of endogenous neural stem cells in adult versus neonatal rats after brachial plexus root avulsion injury

An experimental model of brachial plexus root avulsion injury of cervical dorsal C5-6 was established in adult and neonatal rats.Real-time PCR showed that the levels of brain-derived neurotrophic factor,nerve growth factor and neurotrophin-3 in adult rats increased rapidly 1 day after brachial plexus root avulsion injury,and then gradually decreased to normal levels by 21 days.In neonatal rats,levels of the three neurotrophic factors were decreased on the first day after injury,and then gradually increased from the seventh day and remained at high levels for an extended period of time.We observed that greater neural plasticity contributed to better functional recovery in neonatal rats after brachial plexus root avulsion injury compared with adult rats.Moreover, immunohistochemical staining showed that the number of bromodeoxyuridine/nestin-positive cells increased significantly in the spinal cords of the adult rats compared with neonatal rats after brachial plexus root avulsion injury.In addition,the number of bromodeoxyuridine/glial fibrillary acidic protein-positive cells in adult rats was significantly higher than in neonatal rats 14 and 35 days after brachial plexus injury.Bromodeoxyuridine/β-tubulin-positive cells were not found in either adult or neonatal rats.These results indicate that neural stem cells differentiate mainly into astrocytes after brachial plexus root avulsion injury.Furthermore,the degree of neural stem cell differentiation in neonatal rats was lower than in adult rats.

Penile erectile dysfunction after brachial plexus root avulsion injury in rats

Our previous studies have demonstrated that some male patients suffering from brachial plexus injury, particularly brachial plexus root avulsion, show erectile dysfunction to varying degrees. However, the underlying mechanism remains poorly understood. In this study, we evaluated the erectile function after establishing brachial plexus root avulsion models with or without spinal cord injury in rats. After these models were established, we administered apomorphine （via a sub- cutaneous injection in the neck） to observe changes in erectile function. Rats subjected to simple brachial plexus root avulsion or those subjected to brachial plexus root avulsion combined with spinal cord injury had significantly fewer erections than those subjected to the sham operation. Expression of neuronal nitric oxide synthase did not change in brachial plexus root avulsion rats. However, neuronal nitric oxide synthase expression was significantly decreased in brachial plexus root avulsion ＋ spinal cord injury rats. These findings suggest that a decrease in neuronal nitric oxide synthase expression in the penis may play a role in erectile dysfunction caused by the combi- nation of brachial plexus root avulsion and spinal cord injury.

Influence of species,age and weight on the establishment of a murine model of brachial plexus root avulsion

BACKGROUND： Animal models of brachial plexus root avulsion are required for the study of brachial plexus root injuries. The established ventral approach results in slight injuries, and is similar to mechanisms underlying human brachial plexus root avulsion.OBJECTIVE： To analyze the effects of weight, age, and species on the success rate of brachial plexus root avulsion, and to determine the perfect method for establishing models of brachial plexus root avulsion.DESIGN, TIME AND SETTING： A randomized, block design was performed at the Laboratory of Professor Lihua Zhou, Zhongshan School of Medicine, Sun Yat-sen University, China from June 2008 to June 2009.MATERIALS： Sprague Dawley （SD） rats, golden hamsters, and BALb/C mice were used in the present study.METHODS： All animals were randomly subjected to classical brachial plexus root avulsion and modified brachial plexus root avulsion.MAIN OUTCOME MEASURES： Success rate of brachial plexus root avulsion. RESULTS： The success rate of brachial plexus root avulsion was greater in the modified group than in the classical group （P〈0.01）. Moreover, the difference was significant in 15-day-old SD rats, 5-week-old SD rats, and 3-month-old BALb/C mice （P〈0.01）. The success rate of brachial plexus root avulsion was greater in the same weight, 15-day-old juvenile SD rats, than in the 3-month-old BALb/C mice （classical group, P〈0.01; modified group, P〈0.05）. The success rate of brachial plexus root avulsion was significantly greater in 3-month-old golden hamsters than in 5-week-old SD rats in the classical group （P〈0.05）. The success rate of brachial plexus root avulsion was significantly lower in the 15-day-old SD rats compared with the 5-week-old and 3-month-old SD rats in the classical group （P〈0.01）. However, there was no significant difference in the success rate of brachial plexus root avulsion between various ages of SD rats in the modified group （P〉0.05）.CONCLUSION： Modified surgery to induce brachial plexus root avulsion significantly increases the success rate of model establishment. Species, age, and weight affect the success rate of brachial plexus root avulsion, and species plays an important role in the success rate.

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： ①Functional reconstruction following brachial plexus injury. ②Rehabilitation 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.

A novel extradural nerve transfer technique by coaptation of C4 to C5 and C7 to C6 for treating isolated upper trunk avulsion of the brachial plexus

The study aimed to demonstrate the feasibility of an extradural nerve anastomosis technique for the restoration of a C5 and C6 avulsion of the brachial plexus.Nine fresh frozen human cadavers were used.The diameters,sizes,and locations of the extradural spinal nerve roots were observed.The lengths of the extradural spinal nerve roots and the distance between the neighboring nerve root outlets were measured and compared in the cervical segments.In the spinal canal,the ventral and dorsal roots were separated by the dura and arachnoid.The ventral and dorsal roots of C7 had sufficient lengths to anastomose those of C6.The ventral and dorsal of C4 had enough length to be transferred to those of C5,respectively.The feasibility of this extradural nerve anastomosis technique for restoring C5 and C6 avulsion of the brachial plexus in human cadavers was demonstrated in our anatomical study.

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.

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.

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.

Use of intercostal nerves for different target neurotization in brachial plexus reconstruction

Intercostal nerve transfer is a valuable procedure in devastating plexopathies. Intercostal nerves are a very good choice for elbow flexion or extension and shoulder abduction when the intraplexus donor nerves are not available. The best results are obtained in obstetric brachial plexus palsy patients, when direct nerve transfer is performed within six months from the injury. Unlike the adult posttraumatic patients after median and ulnar nerve neurotization with intercostal nerves, almost all obstetric brachial plexus palsy patients achieve protective sensation in the hand and some of them achieve active wrist and finger flexion. Use in combination with proper muscles, intercostal nerve transfer can yield adequate power to the paretic upper limb. Reinnervation of native muscles(i.e., latissimus dorsi) should always be sought as they can successfully be transferred later on for further functional restoration.

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 C5-7 nerve roots was 100%, while those for C8 and T1 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~ vertebra is a marker for identifying the position of brachial plexus nerve roots.

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.

Is it necessary to use the entire root as a donor when transferring contralateral C7 nerve to repair median nerve？

If a partial contralateral C7 nerve is transferred to a recipient injured nerve, results are not satisfactory. However, if an entire contralateral C7 nerve is used to repair two nerves, both recipient nerves show good recovery. These findings seem contradictory, as the above two methods use the same donor nerve, only the cutting method of the contralateral C7 nerve is different. To verify whether this can actually result in different repair effects, we divided rats with right total brachial plexus injury into three groups. In the entire root group, the entire contralateral C7 root was transected and transferred to the median nerve of the affected limb. In the posterior division group, only the posterior division of the contralateral C7 root was transected and transferred to the median nerve. In the entire root ＋ posterior division group, the entire contralateral C7 root was transected but only the posterior division was transferred to the median nerve. After neurectomy,the median nerve was repaired on the affected side in the three groups. At 8, 12, and 16 weeks postoperatively, electrophysiological examination showed that maximum amplitude, latency, muscle tetanic contraction force, and muscle fiber cross-sectional area of the flexor digitorum superficialis muscle were significantly better in the entire root and entire root ＋ posterior division groups than in the posterior division group. No significant difference was found between the entire root and entire root ＋ posterior division groups. Counts of myelinated axons in the median nerve were greater in the entire root group than in the entire root ＋ posterior division group, which were greater than the posterior division group. We conclude that for the same recipient nerve, harvesting of the entire contralateral C7 root achieved significantly better recovery than partial harvesting, even if only part of the entire root was used for transfer. This result indicates that the entire root should be used as a donor when transferring contralateral C7 nerve.

Modified contralateral C7 nerve transfer: the possibility of permitting ulnar nerve recovery is confirmed by 10 cases of autopsy

Contralateral C7 nerve transfer surgery is one of the most important surgical techniques for treating total brachial plexus nerve injury. In the traditional contralateral C7 nerve transfer surgery, the whole ulnar nerve on the paralyzed side is harvested for transfer, which completely sacrifices its potential of recovery. In the present, novel study, we report on the anatomical feasibility of a modified contralateral C7 nerve transfer surgery. Ten fresh cadavers (4 males and 6 females) provided by the Department of Anatomy, Histology, and Embryology at the Medical College of Fudan University, China were used in modified contralateral C7 nerve transfer surgery. In this surgical model, only the dorsal and superficial branches of the ulnar nerve and the medial antebrachial cutaneous nerve on the paralyzed side (left) were harvested for grafting the contralateral (right) C7 nerve and the recipient nerves. Both the median nerve and deep branch of the ulnar nerve on the paralyzed (left) side were recipient nerves. To verify the feasibility of this surgery, the distances between each pair of coaptating nerve ends were measured by a vernier caliper. The results validated that starting point of the deep branch of ulnar nerve and the starting point of the medial antebrachial cutaneous nerve at the elbow were close to each other and could be readily anastomosed. We investigated whether the fiber number of donor and recipient nerves matched one another. The axons were counted in sections of nerve segments distal and proximal to the coaptation sites after silver impregnation. Averaged axon number of the ulnar nerve at the upper arm level was approximately equal to the sum of the median nerve and proximal end of medial antebrachial cutaneous nerve (left: 0.94:1;right: 0.93:1). In conclusion, the contralateral C7 nerve could be transferred to the median nerve but also to the deep branch of the ulnar nerve via grafts of the ulnar nerve without deep branch and the medial antebrachial cutaneous nerve. The advantage over traditional surgery was that the recovery potential of the deep branch of ulnar nerve was preserved. The study was approved by the Ethics Committee of Fudan University (approval number: 2015-064) in July, 2015.

Comparison between direct repair and humana cellular nerve allografting during contralateral C7 transfer to the upper trunk for restoration of shoulder abduction and elbow flexion

Direct coaptation of contralateral C7 to the upper trunk could avoid the interposition of nerve grafts. We have successfully shortened the gap and graft lengths, and even achieved direct coaptation. However, direct repair can only be performed in some selected cases, and partial procedures still require autografts, which are the gold standard for repairing neurologic defects. As symptoms often occur after autografting, human acellular nerve allografts have been used to avoid concomitant symptoms. This study investigated the quality of shoulder abduction and elbow flexion following direct repair and acellular allografting to evaluate issues requiring attention for brachial plexus injury repair. Fifty-one brachial plexus injury patients in the surgical database were eligible for this retrospective study. Patients were divided into two groups according to different surgical methods. Direct repair was performed in 27 patients, while acellular nerve allografts were used to bridge the gap between the contralateral C7 nerve root and upper trunk in 24 patients. The length of the harvested contralateral C7 nerve root was measured intraoperatively. Deltoid and biceps muscle strength, and degrees of shoulder abduction and elbow flexion were examined according to the British Medical Research Council scoring system;meaningful recovery was defined as M3–M5. Lengths of anterior and posterior divisions of the contralateral C7 in the direct repair group were 7.64 ± 0.69 mm and 7.55 ± 0.69 mm, respectively, and in the acellular nerve allografts group were 6.46 ± 0.58 mm and 6.43 ± 0.59 mm, respectively. After a minimum of 4-year follow-up, meaningful recoveries of deltoid and biceps muscles in the direct repair group were 88.89% and 85.19%, respectively, while they were 70.83% and 66.67% in the acellular nerve allografts group. Time to C5/C6 reinnervation was shorter in the direct repair group compared with the acellular nerve allografts group. Direct repair facilitated the restoration of shoulder abduction and elbow flexion. Thus, if direct coaptation is not possible, use of acellular nerve allografts is a suitable option. This study was approved by the Medical Ethical Committee of the First Affiliated Hospital of Sun Yat-sen University, China (Application ID:[2017] 290) on November 14, 2017.

Functional compensative mechanism of upper limb with root avulsion of C5-C6 of brachial plexus after ipsilateral C7 transfer

Objective： To investigate the compensative mechanism of no further impairment of the upper limb after ipsilateral C7 transfer for treatment of root avulsion of C5-C6 of the brachial plexus. Methods： Sixty Sprague Dawley （SD） rats were randomly divided into a CT-transection group and a control group, 30 rats each. In the CT-transection group, the left forelimbs of the animals underwent transection of ipsilateral C7 nerve root while C5 and C6 nerve roots were avulsed. In the control group, the left forelimbs only underwent C5 and C6 root avulsion. The representative muscles of C7 （innervated mainly by C7） including latissimus dorsi, triceps, extensor carpi radialis brevis and extensor digitorum communis were evaluated with neurophysiological investigation, muscular histology and motor end plate histomorphometry 3, 6 and 12 weeks after operation. The right forelimbs of all rats were taken as the control sides. Results： Three weeks after operation, the recovery rates of amplitudes of compound muscle action potential （CMAP） and CMAP latency, muscular wet weight and cross-sec- tional area of muscle fibers, and area of postsynaptic membranes of those four representative muscles in the C7- transection group were significantly lower than those of the control group （P 〈0.05 or P 〈0.01）. Six weeks postoperatively, the recovery rates of CMAP amplitude and latency of the triceps showed no significant difference between the C7- transection group and the control group （P〉0.05）. For theextensor carpi radialis brevis and the extensor digitorum communis, the recovery rates of the cross-sectional area of muscle fibers, the amplitude and latency of CMAP and the area of postsynaptic membranes showed no significant dif- ference between the two groups （P 〉0.05）, while the rest parameters were still significantly different between the two group （P 〈0.05 or P 〈0.01）. As far as the ultramicrostructure was concerned in the CT-transection group, more motor end plates of four representative muscles were observed and their ultramicrostructure also had a tendency to mature as compared with those of 3 weeks postoperatively. Twelve weeks after operation, all parameters of the CT-transectJon group were not significantly different from those of the control group （P 〉0.05）. In the CT-transection group, the motor end plates were densely distributed and their ultramicrostructure in four representative muscles appeared to be mature as compared with those of the control group. Conclusions： After ipsilateral C7 transfer for treatment of root avulsion of C5-C6 of the brachial plexus, the nerve fibers of the lower trunk can compensatively innervate fibers of Crrepresentative muscles by means of motor end plate regeneration, so there is no further impairment on the injured upper limb.

二期多组神经移位治疗臂丛神经根性撕脱伤的临床应用和疗效

目的分析治疗臂丛神经根性撕脱伤的二期手术方法及其效果。方法2001年8月～2003年4月8例全臂丛神经根性撕脱伤患者,年龄18～38岁。平均伤后6个月内,均应用以下术式治疗。手术步骤:一期手术,膈神经移位至臂丛上干前股,副神经移位至肩胛上神经;健侧C7神经移位至患侧尺神经;二期手术,第4、5、6、7肋间神经移位至桡神经和胸背神经,健侧C7神经经尺神经移位至正中神经。结果术后8例均获随访,时间为二期术后13～25个月,平均21个月。所有患者均有不同程度恢复,相应靶肌肉肌力恢复大于或等于M3为有效恢复,肌皮神经有效恢复6例,恢复率为75.0%;肩胛上神经有效恢复3例,恢复率为37.5%;桡神经有效恢复3例,恢复率为37.5%;胸背神经有效恢复6例,恢复率为75.0%;正中神经有效恢复5例,恢复率为62.5%。感觉恢复情况:正中神经感觉4例为S3,3例为S2,1例为S1。结论二期多组神经移位安全有效,对部分早期臂丛神经损伤并要求缩短手术次数的患者,是一种可选择的方法。

椎管内臂丛前后根的显微解剖及其临床意义

目的:研究臂丛椎管内前后根的显微解剖,为臂丛撕脱伤的诊治提供解剖学基础。方法:在15例防腐灌注红色乳胶的成人尸体的颈胸段标本上,对椎管内臂丛前后根的位置、形态和血供进行观察和测量。结果:臂丛前后根之间有齿状韧带相间隔;前根起始处与脊髓中线的距离从上至下由C5的2.2mm逐渐增大到T1的3.1mm,后根则从C5的4.2mm逐渐减小到T1的2.7mm;前后根与脊髓纵轴的夹角从C5的51.4°、54.8°逐渐减小到T1的21.7°、19.9°;前后根的长度从C5的14.9mm、13.9mm逐渐增大到T1的21.1mm、19.0mm;前后根的直径均以C6最为粗大,分别为2.1mm、3.3mm,后根比相应前根粗;前后根的血供来自椎动脉、颈深动脉和颈升动脉发出的节段性动脉。结论:熟悉臂丛椎管内前后根的显微解剖有助于临床臂丛根性撕脱伤的诊治。