Supplementary Motor Cortical Changes Explored by Resting-State Functional Connectivity in Brachial Plexus Injury

BACKGROUND

Brachial plexus injury (BPI) is a serious peripheral nerve injury, and clinical outcomes are generally unsatisfactory. It has been reported that cortical plasticity could influence the restoration of motor function. However, the neurologic mechanism of BPI is unclear, which provides a basis for further investigation. The supplementary motor area (SMA) plays an important role in the regulation of motor function. This study aims to explore SMA-whole brain functional connectivity after deafferentation of the brachial plexus.

METHODS

Study subjects included 16 patients with BPI and 8 healthy volunteers. The seed region was defined by a block-design functional magnetic resonance imaging program that used unilateral imaginary hand grasp motion as a task stimulus. Next, the voxel-wise functional connectivity between the predefined region and the other regions of the brain was calculated.

RESULTS

We discovered decreased voxel-wise functional connectivity between the SMA and multiple brain regions, including precuneus, posterior cingulum cortex, and anterior cingulum cortex, that are closely associated with information integration or motor processing in patients with BPI.

CONCLUSIONS

Patients with BPI showed weakened functional connectivity between hand grasp-related areas and the SMA and multiple regions associated with motor processing or information integration. A clear image of the functional status of the brain after deafferentation was provided. On the basis of this discovery, a relationship between changes in neuroimaging measurements and clinical outcomes can be determined in future studies.

Different cerebral plasticity of intrinsic and extrinsic hand muscles after peripheral neurotization in a patient with brachial plexus injury: A TMS and fMRI study

Contralateral C7 (CC7) neurotization has been an important approach for brachial plexus injury (BPI). Patients can achieve relatively good grasping function driven by the proximal extrinsic hand muscle (flexor digitorum, FD) after CC7 neurotization, whereas the thumb opposition function driven by the distal intrinsic muscle (abductor pollicis brevis, APB) is poor. The present study aimed to investigate the brain reorganization patterns of the recovery processes of intrinsic and extrinsic hand functions after repairing the median nerve by CC7 neurotization. Transcranial magnetic stimulation (TMS) and functional magnetic resonance imaging (fMRI) were used to evaluate the cerebral plasticity in one BPI patient after CC7 neurotization. After the CC7 neurotization, the patient showed improvements in the paralyzed hand. Combination of TMS and fMRI investigations demonstrated different cortical reshaping patterns of APB and FD. It was also found that the activated cortical areas of FD were located in bilateral motor cortices, but the area of APB was only located in ipsilateral motor cortex. The cerebral plasticity procedure appeared to be different in the gross and fine motor function recovery processes. It provided a new perspective into the cerebral plasticity induced by CC7 neurotization.

Distally based perforator sural flaps for foot and ankle reconstruction

Distally based perforator sural flaps from the posterolateral or posteromedial lower leg aspect are initially a neurofasciocutaneous flap that can be transferred reversely to the foot and ankle region with no need to harvest and sacrifice the deep major artery. These flaps are supplied by a perforating artery issued from the deep peroneal artery or the posterior tibial artery, and the chain-linked adipofascial neurovascular axis around the sural/saphenous nerve. It is a versatile and reliable technique for soft-tissue reconstruction of the heel and ankle region with 180-degrees rotation. In this paper, we present its developing history, vascular basis, surgical techniques including flap design and elevation, flap variations in pedicle and component, surgical indications, and illustrative case reports with different perforating vessels as pivot points for foot and ankle coverage.

The Kinematics and Kinetics Analysis of the Lower Extremity in the Landing Phase of a Stop-jump Task

Large number of studies showed that landing with great impact forces may be a risk factor for knee injuries. The purpose of this study was to illustrate the different landing loads to lower extremity of both genders and examine the relationships among selected lower extremity kinematics and kinetics during the landing of a stop-jump task. A total of 35 male and 35 female healthy subjects were recruited in this study. Each subject executed five experiment actions. Lower extremity kinematics and kinetics were synchronously acquired. The comparison of lower extremity kinematics for different genders showed significant difference. The knee and hip maximum flexion angle, peak ground reaction force and peak knee extension moment have significantly decreased during the landing of the stop-jump task among the female subjects. The hip flexion angle at the initial foot contact phase showed significant correlation with peak ground reaction force during landing of the stop-jump task (r=-0.927, p<0.001). The knee flexion angle at the initial foot contact phase had significant correlation with peak ground reaction force and vertical ground reaction forces during landing of the stop-jump task (r=-0.908, p<0.001; r=0.812, P=0.002). A large hip and knee flexion angles at the initial foot contact with the ground did not necessarily reduce the impact force during landing, but active hip and knee flexion motions did. The hip and knee flexion motion of landing was an important technical factor that affects anterior cruciate ligament (ACL) loading during the landing of the stop-jump task.

Origination of the muscular branches of the median nerve: an electrophysiological study

BACKGROUND

In lower brachial plexus injury, finger flexion after brachialis motor branch transfer is relatively weak. We sought to screen potential branches of the median nerve from the upper trunk for strengthening finger flexion in addition to the brachialis motor branch. However, the spinal origin of the muscular branches of the median nerve based on electrophysiological study was unclear.

OBJECTIVE

To determine the spinal origin of the muscular branches of the median nerve.

METHODS

An intraoperative electrophysiological study was carried out in 18 patients who underwent contralateral C7 nerve transfer. After exposure of the brachial plexus nerve roots on the healthy side, the amplitude of the compound muscle action potential of each median nerve-innervated muscle was recorded while the different nerve roots were stimulated.

RESULTS

The pronator teres received fibers from C5, C6, and C7. It had more contribution from C5 and C6 than from C7 (P<.05). The flexor carpi radialis was innervated mainly by C6 and C7. The nerve branches of the palmaris longus and flexor digitorum superficialis stemmed primarily from C7 and the lower trunk, and no significant difference was found between them (P>.05). The flexor digitorum profundus, flexor pollicis longus, pronator quadratus, and abductor pollicis brevis were innervated predominantly by the lower trunk (P<.05).

CONCLUSION

This electrophysiological study indicates that the pronator teres branch might be the most feasible alternative donor nerve to supplement the brachialis motor branch and strengthen finger flexion after lower brachial plexus injury.

Contralateral Peripheral Neurotization for Hemiplegic Upper Extremity After Central Neurologic Injury

BACKGROUND:

Central neurological injury (CNI) is a major contributor to physical disability that affects both adults and children all over the world. The main sequelae of chronic stage CNI are spasticity, paresis of specific muscles, and poor selective motor control. Here, we apply the concept of contralateral peripheral neurotization in spasticity releasing and motor function restoration of the affected upper extremity.

OBJECTIVE:

A clinical investigation was performed to verify the clinical efficacy of contralateral C7 neurotization for rescuing the affected upper extremity after CNI.

METHODS:

In the present study, 6 adult hemiplegia patients received the nerve transfer surgery of contralateral C7 to C7 of the affected side. Another 6 patients with matched pathological and demographic status were assigned to the control group that received rehabilitation only. During the 2-year follow-up, muscle strength of bilateral upper extremities was assessed. The Modified Ashworth Scale and Fugl-Meyer Assessment Scale were used for evaluating spasticity and functional use of the affected upper extremity, respectively.

RESULTS:

Both flexor spasticity release and motor functional improvements were observed in the affected upper extremity in all 6 patients who had surgery. The muscle strength of the extensor muscles and the motor control of the affected upper extremity improved significantly. There was no permanent loss of sensorimotor function of the unaffected upper extremity.

CONCLUSION:

This contralateral C7 neurotization approach may open a door to promote functional recovery of upper extremity paralysis after CNI.

Restoration of hand function in C7-T1 brachial plexus palsies using a staged approach with nerve and tendon transfer

Brachial plexus palsies of C7-T1 result in the complete loss of hand function, including finger and thumb flexion and extension as well as intrinsic muscle function. The task of reanimating such a hand remains challenging, and so far there has been no reliable neurological reconstructive method for restoring hand function. The authors aimed to establish a reliable strategy to reanimate the paralyzed hand. Two patients had sustained C7-T1 complete lesions. In the first stage of the operative procedure, a supinator motor branch to posterior interosseous nerve transfer was performed with brachialis motor branch transfer to the median nerve to restore finger and thumb extension and flexion. In the second stage, the intact brachioradialis muscle was used for abductorplasty to restore thumb opposition. Both patients regained good finger extension and flexion. Thumb opposition was also attained, and overall hand function was satisfactory. The described strategy proved effective and reliable in restoring hand function after C7-T1 brachial plexus palsies.

Pronator Teres Branch Transfer to the Anterior Interosseous Nerve for Treating C8T1 Brachial Plexus Avulsion

BACKGROUND:

The treatment of C8T1 avulsion is challenging for neurosurgeons. Various methods for the restoration of finger flexion are used. However, most of these methods have different disadvantages and cannot restore the full active range of motion of the fingers.

OBJECTIVE:

To determine the feasibility of the pronator teres branch transfer to the anterior interosseous nerve with anatomic study and to use this method in 1 case.

METHODS:

The upper limbs of 15 fresh cadavers were dissected to identify the main trunk of the median nerve, the pronator teres branch, and the anterior interosseous nerve. The mean number and length of the pronator teres branches were recorded. The anterior interosseous nerve was dissected atraumatically to the most proximal level where the fibers of the anterior interosseous nerve did not mingle with the fibers of the main trunk of the median, which was defined as the atraumatic level of the anterior interosseous nerve. A line joining the most protruding point of the medial condyle and lateral condyle of the humerus was used as a measurement landmark. Pronator teres branch transfer to the anterior interosseous nerve was performed in 1 patient with C8T1 avulsion.

RESULTS:

The mean number of the pronator teres branches was 2.37 ± 0.49. The mean length of the pronator teres branches was 9.64 ± 0.71 mm. The mean distance between the point where the pronator teres branches originated and the landmark line was 3.87 ± 0.34 mm. The mean distance between the atraumatic level of the anterior interosseous nerve and the landmark line was −5.46 ± 0.73 mm. Transfer of the pronator teres was used to innervate the anterior interosseous nerve in 1 patient with C8T1 avulsion. When assessed 14 months after the operation, a full active range of motion of the fingers had been restored, and the patient's finger flexor muscles had regained grade 4 power.

CONCLUSION:

The pronator teres can be transferred to the anterior interosseous nerve directly at the elbow level. This operation was performed successfully in 1 patient, who exhibited finger flexion recovery.

A pseudo-planar metasurface for a polarization rotator

New demonstrations of effective interaction between light and artificially electromagnetic interface, or the metasurface, have stimulated intensive research interests on control of light to realize applications in beam steering, optical imaging and light focusing, etc. Here we reported a new type of planar metasurface of which every individual metamolecule is single metallic layer with stereo structure and the metasurface is name as Pseudo-Planar Metasurface (PPM). The metamolecule of the PPM is a chiral structure and therefore derives significant optical activity.

Deactivation of distant pain-related regions induced by 20-day rTMS: a case study of one-week pain relief for long-term intractable deafferentation pain

BACKGROUND

Deafferentation pain secondary to brachial plexus avulsion, spinal cord injury, and other peripheral nerve injuries is often refractory to conventional treatments. Stimulation of the primary motor cortex (M1) has been proven to be an effective treatment for intractable deafferentation pain. The mechanisms underlying the attenuation of deafferentation pain by motor cortex stimulation remain hypothetical.

OBJECTIVES

The purpose of this case report is to: (1) summarize a case in which a patient suffering chronic intractable deafferentation pain for 25 years underwent rTMS treatment over M1, (2) describe the evidence from PET imaging, and (3) reveal a possible relief mechanism with cortical plasticity.

STUDY DESIGN

Case report.

SETTING

University hospital.

RESULTS

This patient had successful pain control with no transient or lasting side effects. The pain relief remained stable for at least one week. At the end of the 20-day procedure, pain relief was obtained according to the Visual Analog Scale (VAS) (-34.6%) and the McGill Pain Questionnaire (MPQ) (-31.6%). In the PET/CT scans, the glucose metabolism was significantly reduced contralaterally to the pain side in the anterior cingulate cortex (ACC), insula, and caudate nucleus. There was no statistically significant difference in any other cortical area.

LIMITATIONS

Single case of a patient with long-term intractable deafferentation pain having a PET study.

CONCLUSION

This study implies that a single session of 20 Hz rTMS over the motor cortex could reduce the pain level in patients suffering from long-term, intractable deafferentation pain. The stimulation of the M1 induces deactivation in the ACC, insula, and caudate nucleus. The changes in these pain-related regions may mirror an adaptive mechanism to pain relief after rTMS treatment.

Arthroscopic distal metaphyseal ulnar shortening osteotomy for ulnar impaction syndrome: a different technique

Ulnar impaction syndrome generally occurs with positive ulnar variance. The solution to the problem is to unload the ulnocarpal joint. Effective surgical options include diaphyseal ulnar shortening osteotomy, open wafer osteotomy, and arthroscopic wafer osteotomy. Recently, Slade and Gillon described an open procedure of ulnar shortening in the osteochondral region of the ulnar head. The procedure minimizes the risk of hemarthrosis and does not require hardware removal, which are problems with other surgical options. This article introduces a new arthroscopic technique of distal metaphyseal ulnar shortening osteotomy for ulnar impaction syndrome. This technique offers the advantages of minimizing surgical injury to the dorsal capsule of the distal radoulnar joint and so protects its stability.

Sensory restoration in cortical level after a contralateral C7 nerve transfer to an injured arm in rats

BACKGROUND

The restoration of sensory and motor function in brachial plexus root avulsion patients is a difficult challenge. The central nervous system plays an important role in sensory recovery after peripheral nerve injury and repair.

OBJECTIVE

To investigate the sensory restoration process after surgery at the cortical level in rodent models with a contralateral C7 nerve transfer.

METHODS

Thirty-five male Sprague-Dawley rats were used in this experiment, and both behavioral tests and somatosensory evoked potentials were used to investigate the sensory function recovery of the injured forepaws and the cortical reorganization in the rats postoperatively.

RESULTS

The results demonstrated a dynamic change in the ipsilateral somatosensory cortex, both in the shape and location, where overlapping sensory cortical representations of the healthy and injured forepaws were observed consistently. Behavioral tests show that the sensation first occurred only in the healthy forepaw and later in both when stimulating the injured one, which suggested a tendency of the sensation function to recover in the injured forepaws of the rats as time progressed.

CONCLUSION

The cortical reorganization occurred only in the ipsilateral hemisphere, which is different from the motor cortex reorganization using the same model as that described in a previous study. This reorganization pattern offers an interpretation of the unique sensory recovery process after the transfer of the C7 nerve to the contralateral median nerve, but also provides the basis for further sensory restoration in clinical practice.

Long-term ongoing cortical remodeling after contralateral C-7 nerve transfer

Object

Contralateral C-7 nerve transfer was developed for the treatment of patients with brachial plexus avulsion injury (BPAI). In the surgical procedure the affected recipient nerve is connected to the ipsilateral motor cortex, and the dramatic peripheral alteration may trigger extensive cortical reorganization. However, little is known about the long-term results after such specific nerve transfers. The purpose of this study was to investigate the long-term cortical adaptive plasticity after BPAI and contralateral C-7 nerve transfer.

Methods

In this study, 9 healthy male volunteers and 5 male patients who suffered from right-sided BPAI and had undergone contralateral C-7-transfer more than 5 years earlier were included. Functional MRI studies were used for the investigation of long-term cerebral plasticity.

Results

The neuroimaging results suggested that the ongoing cortical remodeling process after contralateral C-7 nerve transfer could last for a long period; at least for 5 years. The motor control of the reinnervated limb may finally transfer from the ipsilateral to the contralateral hemisphere exclusively, instead of the bilateral neural network activation.

Conclusions

The authors believe that the cortical remodeling may last for a long period after peripheral rearrangement and that the successful cortical transfer is the foundation of the independent motor recovery.

Outcome after transfer of intercostal nerves to the nerve of triceps long head in 25 adult patients with total brachial plexus root avulsion injury

OBJECT

The intercostal nerves (ICNs) have been used to repair the triceps branch in some organizations in the world, but the reported results differ significantly. The effect of this procedure requires evaluation. Thus, this study aimed to evaluate the outcome of ICN transfer to the nerve of the long head of the triceps muscle and to determine the factors affecting the outcome of this procedure.

METHODS

A retrospective review was conducted in 25 patients with global root avulsion brachial plexus injuries who underwent ICN transfer. The nerves of the long head of the triceps were the recipient nerves in all patients. The ICNs were used in 2 different ways: 2 ICNs were used as donor nerves in 18 patients, and 3 ICNs were used in 7 patients. The mean follow-up period was 5.6 years.

RESULTS

The effective rate of motor recovery in the 25 patients was 56% for the function of the long head of the triceps. There was no significant difference in functional recovery between the patients with 2 or 3 ICN transfers. The outcome of this procedure was not altered if combined with phrenic nerve transfer to the biceps branch. Patients in whom surgery was delayed 6 months or less achieved better results.

CONCLUSIONS

The transfer of ICNs to the nerve of long head of the triceps is an effective procedure for treating global brachial plexus avulsion injuries, even if combined with phrenic nerve transfer to the biceps branch. Two ICNs appear to be sufficient for donation. The earlier the surgery is performed, the better are the results achieved.

Spinal nerve origins of the muscular branches of the radial nerve: an electrophysiological study

BACKGROUND

In injuries of the lower brachial plexus, finger flexion can be restored by nerve or tendon transfer. However, there is no technique that can guarantee good recovery of finger and thumb extension.

OBJECTIVE

To determine the spinal nerve origins of the muscular branches of the radial nerve and identify potential intraplexus donor nerves for neurotization of the posterior interosseous nerve in patients with lower brachial plexus injuries.

METHODS

An intraoperative electrophysiological study was carried out during 16 contralateral C7 nerve transfers. The compound muscle action potential of each muscle innervated by the radial nerve was recorded while the C5-T1 nerves were individually stimulated.

RESULTS

The triceps brachii muscle primarily received root contributions from C7. The C5 and C6 nerve roots displayed greater amplitudes for the brachioradialis and supinator muscles compared with those of the C7, C8, and T1 nerve roots (P < .05). The extensor carpi radialis branch was innervated by C5, C6, and C7, and no significant differences were detected between them (P > .05). The amplitudes obtained for the extensor digitorum communis branch were the largest from C7 and C8, without a significant difference between them (P > .05), whereas the amplitudes of the extensor carpi ulnaris and extensor pollicis longus were largest from the C8 root (P < .05).

CONCLUSION

The supinator muscle branch is likely the best donor nerve for the repair of lower brachial plexus injuries affecting muscles that are innervated by the posterior interosseous nerve.

Clinical research of comprehensive rehabilitation in treating brachial plexus injury patients

BACKGROUND

Brachial plexus injury is one of the difficult medical problems in the world. The aim of this study was to observe the clinical therapeutic effect of comprehensive rehabilitation in treating dysfunction after brachial plexus injury.

METHODS

Forty-three cases of dysfunction after brachial plexus injury were divided into two groups randomly. The treatment group, which totaled 21 patients (including 14 cases of total brachial plexus injury and seven cases of branch brachial plexus injury), was treated with comprehensive rehabilitation including transcutaneous electrical nerve stimulation, mid-frequency electrotherapy, Tuina therapy, and occupational therapy. The control group, which totaled 22 patients (including 16 cases of total brachial plexus injury and six cases of branch brachial plexus injury), was treated with home-based electrical nerve stimulation and occupational therapy. Each course was of 30 days duration and the patients received four courses totally. After four courses, the rehabilitation effect was evaluated according to the brachial plexus function evaluation standard and electromyogram (EMG) assessment.

RESULTS

In the treatment group, there was significant difference in the scores of brachial plexus function pre- and post-treatment (P < 0.01) in both "total" and "branch" injury. The scores of two "total injury" groups had statistical differences (P < 0.01), while the scores of two "branch injury" groups had statistical differences (P < 0.05) after four courses. EMG suggested that the appearance of regeneration potentials of the recipient nerves in the treatment group was earlier than the control group and had significant differences (P < 0.05).

CONCLUSION

Comprehensive rehabilitation was more effective in treating dysfunction after brachial plexus injury than nonintegrated rehabilitation.

Semiquantifying of fascicles of the C7 spinal nerve in the upper and lower subscapular nerves innervating the subscapularis and its clinical inference in Erb's palsy

To elucidate anatomic basis of susceptibility for contracture of the subscapularis muscle in Erb's palsy of the brachial plexus, we semiquantitatively studied the spinal nerve origins of the subscapular nerves innervating the subscapularis, with special reference to the contribution of C7 innervation to the subscapularis. Thirty-three sides of formalin-fixed upper extremities were dissected to obtain the intact brachial plexus. After immersed in 10% acetic acid for 2 weeks, the upper and lower subscapular nerves innervating the whole subscapularis, were dissected retrogradely to verify their spinal nerve origins. The cross-sectional area by C7 innervation and that by the upper trunk innervation was calculated respectively to obtain the constituent percentage of different components in the upper and lower subscapular nerves. In the upper subscapular nerve, fascicles of C7 accounted for 0% (interquartile range, 0-1.1%) of cross-sectional area and those of the upper trunk, 100% (98.9-100%). In the lower subscapular nerve, fascicles of C7 accounted for 40.5% (23.5-47.5%) and those of the upper trunk, 59.5% (52.5-76.5%). In total, 18.6% (13.3-27.3%) of fascicles in the subscapular nerves innervating the subscapularis originated from C7, while 81.4% (72.7-86.7%) of those came from the upper trunk. It is confirmed that innervation of the subscapularis originates from more spinal cord segments than that of infraspinatus and teres minor, and this may be the main reason for which in Erb's palsy, functional recovery of the subscapularis is often faster than that of lateral rotators of the shoulder, resulting in medial rotation contracture of the shoulder.

Contralateral C7 nerve transfer - Our experiences over past 25 years

Contralateral C7 nerve transfer has been used in treating brachial plexus avulsion injury since 1986. During the past two and half decades, much has been achieved, yet more needs to be explored. In this review article, the indications, technical details, outcome and pitfalls of this technique are summarized.

Partial Ipsilateral C7 Transfer to the Upper Trunk for C5-C6 Avulsion of the Brachial Plexus

BACKGROUND:

Ipsilateral whole C7 root transfer has been reported in treating C5-C6 avulsion. To minimize donor deficits, partial ipsilateral C7 (PIC7) transfer was developed.

OBJECTIVE:

To investigate the long-term results of PIC7 transfer to the upper trunk in treating C5-C6 avulsion of the brachial plexus.

METHODS:

We prospectively studied 8 young adults with C5-C6 avulsion. Five patients (group A) who also had spinal accessory nerve (SAN) injury underwent PIC7 transfer to the upper trunk. The other 3 patients (group B) without SAN injury underwent a combination of PIC7 to the upper trunk and the SAN to the suprascapular nerve (SSN). Postsurgical evaluations including donor deficits, functional recovery, and co-contraction of the muscles were performed 1 week later and then at intervals of 3 months.

RESULTS:

After a mean period of 39.2 months, all subjects were found to have gained elbow flexion of 110 to 150° with muscle strength of M4-5. The patients in group B achieved external rotation of 60 to 70° at M3-4, and 2 achieved shoulder abductions approaching 180° at M4. The patients in group A showed no active external rotation and shoulder abduction of 25 to 50° at M2-3. The temporary deficits caused by PIC7 transfer disappeared in all subjects within the first 3 months. Co-contraction of the latissimus dorsi against the deltoid was recorded in group A but not in group B.

CONCLUSION:

PIC7 transfer, when combined with SAN transfer to SSN as a novel approach, is a safe, easy, and efficacious surgical procedure for patients with simple C5-C6 avulsion.

Randomized, double-blind, and placebo-controlled trial of clenbuterol in denervated muscle atrophy

Objectives. β₂-adrenergic agonists, such as clenbuterol, have been shown to promote the hypertrophy of healthy skeletal muscles and to ameliorate muscle wasting in a few pathological conditions in both animals and humans. We intended to investigate the clinical efficacy of clenbuterol on attenuating denervation-induced muscle atrophy. Methods. A double-blind, placebo-controlled, parallel, and randomized trial was employed. 71 patients, suffering from brachial plexus injuries, were given either clenbuterol (60 μg, bid) or placebo for 3 months. Before and at the end of the study, patients were given physical examinations, biopsies of biceps brachii, electromyograms (EMGs), and other laboratory tests. Results. Compared with placebo treatment, clenbuterol significantly mitigated the decreases in cross-sectional areas of type I and II muscle fibers and alleviated the reduction in fibrillation potential amplitudes, without any adverse effects. Conclusions. Clenbuterol safely ameliorated denervated muscle atrophy in this cohort; thus larger clinical studies are encouraged for this or other β₂ agonists on denervation-induced muscle atrophy.

BDNF and GAP43 contribute to dynamic transhemispheric functional reorganization in rat brain after contralateral C7 root transfer following brachial plexus avulsion injuries

It is known that contralateral seventh cervical nerve (C7) root transfer after brachial plexus avulsion injuries (BPAI) causes interhemispheric cortical functional reorganization. However, the potential mechanisms and the role of neurotrophic factors and/or growth-associated protein expression in the process of cerebral reorganization are not well understood. The present study identified the expression of brain-derived neurotrophic factor (BDNF) and growth-associated protein 43 (GAP43) mRNA in primary motor cortex after contralateral C7 root transfer following BPAI. BDNF and GAP43 mRNA levels were significantly increased in brain samples at both 6 and 9 months after contralateral C7 root transfer following BPAI, in comparison with the samples from the rats with BPAI only. These findings indicate that BDNF and GAP43 may play an important role during the dynamic transhemispheric functional reorganization.

Selective Neurotization of the Radial Nerve in the Axilla Using a Full-Length Phrenic Nerve to Treat Complete Brachial Plexus Palsy: An Anatomic Study and Case Report

BACKGROUND:

Current methods for the restoration of wrist and digit extension after a complete brachial plexus injury result in poor outcomes.

OBJECTIVE:

To determine the internal topography of the radial nerve in the axilla and present a method for selective neurotization of the radial nerve using a full-length phrenic nerve.

METHODS:

Internal topographic features of the fascicular groups of the radial nerve were observed at the level of latissimus dorsi insertion in 16 cadavers. Selective neurotization of the medial portion of the antebrachial part of the main trunk of the radial nerve was performed at this level using a full-length phrenic nerve in one patient with complete brachial plexus palsy.

RESULTS:

At the level of latissimus dorsi insertion in the axilla, the antebrachial part of the radial nerve, which innervates the forearm extensors, is located at the superior lateral part of the radial nerve trunk. It can be divided into medial and lateral portions. Transfer of a full-length phrenic nerve was used to selectively reinnervate the medial portion of the antebrachial part of the radial nerve in 1 patient with complete brachial plexus palsy. The patient's antebrachial extensor muscles regained Grade 4 power when assessed 3 years after surgery.

CONCLUSION:

The fibers that innervate the antebrachial extensors are located at the superior lateral part of the radial nerve trunk in the axilla. Selective neurotization of the radial nerve at this level with a phrenic nerve was performed successfully in 1 patient.