Contralateral C7 Nerve Transfer Research Articles

Electrophysiologic recovery of the abductor pollicis brevis after contralateral C7 nerve transfer in 95 patients with global brachial plexus avulsion

In this study, we investigated the electrophysiologic recovery of the abductor pollicis brevis (APB) muscle after contralateral seventh cervical (cC7) nerve transfer for the treatment of global brachial plexus avulsion (GBPA). We retrospectively analyzed the electromyography records of 95 patients with GBPA, comprising 81 men and 14 women, focusing on the motor unit potential (MUP) recovery of the APB. All patients underwent cC7–median nerve (MN) transfer. The cC7 nerve was transferred to the MN alone in 58 patients (One-Nerve Group), whereas 37 patients underwent cC7 transfer to the MN and another nerve (Two-Nerve Group). Fifty-three patients (MUP Group) exhibited MUP recovery of the APB, whereas 42 patients did not (No-MUP Group). The MUP Group comprised 32 patients from the One-Nerve Group and 21 patients from the Two-Nerve Group. The mean age of the MUP Group was significantly lower than that of the No-MUP Group. In summary, electrophysiologic recovery of the APB was common in patients with GBPA after cC7–MN transfer, indicating that it may be possible to restore the function of the intrinsic muscles of the hand after GBPA. The rehabilitation strategy for patients with GBPA, which overlooks the restoration of intrinsic hand muscle function, may require amendment.

Retropharyngeal Contralateral C7 Nerve Transfer to the Lower Trunk for Brachial Plexus Birth Injury: Technique and Results.

Brachial plexus birth injuries with multiple nerve root avulsions present a particularly difficult reconstructive challenge because of the limited availability of donor nerves. The contralateral C7 has been described for brachial plexus reconstruction in adults but has not been well-studied in the pediatric population. We present our technique and results for retropharyngeal contralateral C7 nerve transfer to the lower trunk for brachial plexus birth injury. We performed a retrospective review. Any child aged less than 2 years was included. Charts were analyzed for patient demographic data, operative variables, functional outcomes, complications, and length of follow-up. We had a total of 5 patients. Average nerve graft length was 3 cm. All patients had return of hand sensation to the ulnar nerve distribution as evidenced by a pinch test, unprompted use of the recipient limb without mirror movement, and an Active Movement Scale (AMS) of at least 2/7 for finger and thumb flexion; one patient had an AMS of 7/7 for finger and thumb flexion. Only one patient had return of ulnar intrinsic hand function with an AMS of 3/7. Two patients had temporary triceps weakness in the donor limb and one had clinically insignificant temporary phrenic nerve paresis. No complications were related to the retropharyngeal nerve dissection in any patient. Average follow-up was 3.3 years. The retropharyngeal contralateral C7 nerve transfer is a safe way to supply extra axons to the severely injured arm in brachial plexus birth injuries with no permanent donor limb deficits. Early functional recovery in these patients, with regard to hand function and sensation, is promising. Therapeutic V.

Proteomic analysis of trans-hemispheric motor cortex reorganization following contralateral C7 nerve transfer.

Nerve transfer is the most common treatment for total brachial plexus avulsion injury. After nerve transfer, the movement of the injured limb may be activated by certain movements of the healthy limb at the early stage of recovery, i.e., trans-hemispheric reorganization. Previous studies have focused on functional magnetic resonance imaging and changes in brain-derived neurotrophic factor and growth associated protein 43, but there have been no proteomics studies. In this study, we designed a rat model of total brachial plexus avulsion injury involving contralateral C7 nerve transfer. Isobaric tags for relative and absolute quantitation and western blot assay were then used to screen differentially expressed proteins in bilateral motor cortices. We found that most differentially expressed proteins in both cortices of upper limb were associated with nervous system development and function (including neuron differentiation and development, axonogenesis, and guidance), microtubule and cytoskeleton organization, synapse plasticity, and transmission of nerve impulses. Two key differentially expressed proteins, neurofilament light (NFL) and Thy-1, were identified. In contralateral cortex, the NFL level was upregulated 2 weeks after transfer and downregulated at 1 and 5 months. The Thy-1 level was upregulated from 1 to 5 months. In the affected cortex, the NFL level increased gradually from 1 to 5 months. Western blot results of key differentially expressed proteins were consistent with the proteomic findings. These results indicate that NFL and Thy-1 play an important role in trans-hemispheric organization following total brachial plexus root avulsion and contralateral C7 nerve transfer.

Contralateral C7 Nerve Root Transfer for Function Recovery in Adults: A Meta-analysis.

Background:Root avulsion to all 5 roots of the brachial plexus is a common presentation and keeps a major reconstructive challenge. The contralateral C7 (CC7) nerve transfer has been used in treating brachial plexus avulsion injury (BPAI) since 1986. However, the effectiveness of the procedure remains a subject of controversy. The aim of this meta-analysis was to study surgical outcomes regarding motor and sensory recovery after CC7 nerve transfer.Methods:Chinese or English (i.e., “contralateral c-7”, “contralateral c7”, “c7 nerve root”, and “seventh cervical nerve root”) keywords were used for a literature search for articles related to CC7 nerve transfer in several databases (i.e., PubMed, Cochrane, Embase, CNKI, CQVIP, and Wanfang Data). Clinical research articles were screened, and animal studies as well as duplicate publications were excluded. Muscle strength and sensory recovery were considered to be effective only when the scores on the United Kingdom Medical Research Council scale were equal to or higher than M3 and S3, respectively.Results:The overall ipsilateral recipient nerve recovery rates were as follows: the efficiency rate for muscle strength recovery after CC7 nerve transfer was 0.57 (95% confidence interval [CI]: 0.48–0.66) and for sensory recovery was 0.52 (95% CI: 0.46–0.58). When the recipient nerve was the median nerve, the efficiency rate for muscle strength recovery was 0.50 (95% CI: 0.39–0.61) and for sensory was 0.56 (95% CI: 0.50–0.63). When the recipient nerve was the musculocutaneous nerve and the radial nerve, the efficiency rate for muscle strength recovery was 0.74 (95% CI: 0.65–0.82) and 0.50 (95% CI: 0.31–0.70), respectively.Conclusions:Transfer of CC7 nerves to musculocutaneous nerves leads to the best results. CC7 is a reliable donor nerve, which can be safely used for upper limb function reconstruction, especially for entirely BPAI. When modifying procedures, musculocutaneous nerves and median nerve can be combined as recipient nerves.

Cerebral plasticity after contralateral cervical nerve transfer in human by longitudinal PET evaluation

ObjectThe treatment of brachial plexus avulsion injury remains a challenging problem. Admittedly, central nervous mechanisms play a significant role in the motor recovery of the paralyzed hand after peripheral nerve surgery. The present study aimed at investigating the relationship between cerebral reorganization and motor recovery after a unique peripheral crossing nerve transfer surgery in brachial plexus injury patients. MethodsIn the present study, two brachial plexus avulsion injury patients with were followed up for 4 years after contralateral C7 nerve transfer surgery. In the surgery, an intact nerve root from the intact limb was transferred to repair the injured nerves. One patient showed a good motor recovery in the paralyzed hand while the other showed relatively poor outcomes. In the longitudinal follow-up, 9 PET scans of the brain were conducted in both patients at regular intervals of every 6 months. A correlation analysis between cerebral glucose metabolism and flexion power of the paralyzed wrists and fingers was performed to investigate the involvement of brain reorganization during the process of motor recovery. ResultsThe cerebral glucose metabolism in the corpus callosum, premotor cortex (Broadmann Area 6) and the precuneus were found positively correlated with the motor recovery of the paralyzed hand in Patient A (P < .01). Positive correlation between the cerebral glucose metabolism and the motor recovery of the paralyze hand was only present in the corpus callosum in Patient B (P < .01). ConclusionCorpus callosum, premotor cortex and precuneus were related with motor recovery after contralateral cervical nerve transfer surgery. The accumulating activation of these cortical regions potentially represented the recovery of high-order motor networks and may have facilitated the motor recovery.

Functional connectivity of motor cortical network in patients with brachial plexus avulsion injury after contralateral cervical nerve transfer: a resting-state fMRI study

IntroductionThe purpose of this study is to assess the functional connectivity of the motor cortical network in patients with brachial plexus avulsion injury (BPAI) after contralateral C7 nerve transfer, using resting-state functional magnetic resonance imaging (RS-fMRI).MethodsTwelve patients with total brachial plexus root avulsion underwent RS-fMRI after contralateral C7 nerve transfer. Seventeen healthy volunteers were also included in this fMRI study as controls. The hand motor seed regions were defined as region of interests in the bilateral hemispheres. The seed-based functional connectivity was calculated in all the subjects. Differences in functional connectivity of the motor cortical network between patients and healthy controls were compared.ResultsThe inter-hemispheric functional connectivity of the M1 areas was increased in patients with BPAI compared with the controls. The inter-hemispheric functional connectivity between the supplementary motor areas was reduced bilaterally.ConclusionsThe resting-state inter-hemispheric functional connectivity of the bilateral M1 areas is altered in patients after contralateral C7 nerve transfer, suggesting a functional reorganization of cerebral cortex.

Transfert robot-assisté de la racine C7 du côté controlatéral sain : étude de faisabilité sur cadavre

Patients with cerebral palsy and spastic hemiplegia may have extremely poor upper extremity function. Unfortunately, many current therapies and treatments for patients with spastic hemiplegia offer very limited improvements. One innovative technique for treating these patients is to use a contralateral C7 nerve root transfer to neurotize the C7 nerve root in the affected limb. This may result not only in less spasticity in the affected limb, but also improved control and motor function vis-a-vis the new connection to the normal cerebral hemisphere. However, contralateral C7 transfers can require large incisions and long nerve grafts. The aim of this study was to test the feasibility of a contralateral C7 nerve root transfer procedure with the use of a minimally invasive robot-assisted technique. In a cadaveric experiment, both sides of C7 root were dissected. The right recipient C7 root was resected as proximally as possible, while the left donor C7 root was resected as distally as possible. With the use of the robot Da Vinci SIy (Intuitive Surgical™, Sunnyvale, CA, USA), we were able to eliminate the large incision and use a much shorter nerve graft when performing the contralateral C7 nerve transfer.

Contralateral C7 Transfer via Both Vascularized Ulnar Nerve and Medial Antebrachial Cutaneous Nerve With the Ulnar Artery Anastomosed to the Arteria transversa Colli to Repair Brachial Plexus Avulsion

Background: Contralateral C7 nerve transfer to the median nerve has been used in an attempt to restore finger flexion in patients with total brachial plexus avulsion injury. However, the results have not been satisfactory mainly because of the requirement to use a long bridging nerve graft, which causes an extended nerve regeneration process and irreversible muscle atrophy. A new procedure involving contralateral C7 nerve transfer via both vascularized ulnar nerve and medial antebrachial cutaneous nerve with the ulnar artery anastomosed to the arteria transversa colli is presented here. Methods: It was performed in 25 patients with total brachial plexus avulsion injury. Contralateral C7 nerve root was coapted to the distal end of the ipsilateral vascularized ulnar nerve and medial antebrachial cutaneous nerve with the ulnar artery is anastomosed to the arteria transversa colli. The ulnar nerve was secured to the median nerve, and medial antebrachial cutaneous nerve was used to repair musculocutaneous nerve. Electromyography and ultrasonography were used to evaluate the early recovery. Recovery of finger, wrist, and elbow flexion was evaluated with the use of the modified British Medical Research Council muscle grading system. Results: Electromyography showed the early recovery by 3 months postoperatively, and smooth blood flow at the anastomotic stoma can be seen through ultrasound. The mean follow-up period (and standard deviation) was 20 ± 6 months. Motor function with a grade of M3+ or greater was attained in 60% of the patients for elbow flexion, 64% of the patients for finger flexion, 53% of the patients for thumb flexion, and 72% of the patients for wrist flexion. Conclusions: Contralateral C7 nerve transfer via both vascularized ulnar nerve and medial antebrachial cutaneous nerve with the ulnar artery anastomosed to the arteria transversa colli speeds up the nerve regeneration in patients with total brachial plexus avulsion injury and improve the utilization of contralateral C7 fiber. There was satisfactory recovery of finger flexion and wrist flexion in this series.

Outcome of Contralateral C7 Nerve Transfer in the Treatment of Total Brachial Plexus Root Avulsion Injury Patient

Objective: The objective of this study was to evaluate the outcome of patients treated with contralateral C7 (cC7) transfer and to determine the factors that affect the outcome of this procedure. Materials and Methods: A retrospective review of 73 patients with total brachial plexus root avulsion injury (BPAI) who underwent cC7 transfer was conducted. All of the surgeries were performed by 2 stages, and the pedicled ulnar nerve was the bridged nerve. The 73 patients were divided into 2 groups according to different number of the recipient nerves. In group 1 (51 patients), the cC7 nerve was used to transfer to median nerve only. The entire cC7 was used in 11 patients; the posterior division together with the lateral part of the anterior division was used to transfer to median nerve in 15 patients; and the anterior or the posterior division alone was used to transfer to median nerve in 25 patients. In group 2, the cC7 nerve was used to transfer to 2 nerves simultaneously. The entire cC7 was used to transfer to median nerve and biceps branch in 12 patients and to median nerve and triceps branch in 10 patients. The mean follow-up period was 7.3 years. Results: The efficient of these 73 patients was 54.8% in wrist and finger flexor, 57.5% in median nerve area sensation, 66.7% in the elbow flexor, and 20% in the elbow extensor. The patients with entire cC7 root transfer achieved significantly better recovery than the patients with partial cC7 root transfer. The best function recovery could be induced if the interval between 2 stages was 4 to 8 months. Functional recovery of biceps branch was significantly better than that of triceps branch. Conclusion: Contralateral C7 transfer is an effective procedure in treating total BPAI patients. If transferred to single nerve, the entire C7 root transfer can obtain significantly better recovery, and we emphasize using the entire root as the donor. The optimal interval between 2 surgery stages is 4 to 8 months. If transferred to 2 nerves, the 2 recipient nerves should be collaborative in motor function.

Robot-assisted C7 nerve root transfer from the contralateral healthy side: A preliminary cadaver study

Patients with cerebral palsy and spastic hemiplegia may have extremely poor upper extremity function. Unfortunately, many current therapies and treatments for patients with spastic hemiplegia offer very limited improvements. One innovative technique for treating these patients is the use a contralateral C7 nerve root transfer to neurotize the C7 nerve root in the affected limb. This may result not only in less spasticity in the affected limb, but also improved control and motor function vis-a-vis the new connection to the normal cerebral hemisphere. However, contralateral C7 transfers can require large incisions and long nerve grafts. The aim of this study was to test the feasibility of a contralateral C7 nerve root transfer procedure with the use of a prevertebral minimally invasive robot-assisted technique. In a cadaver, both sides of the C7 root were dissected. The right recipient C7 root was resected as proximally as possible, while the left donor C7 root was resected as distally as possible. With the use of the da Vinci ® SI surgical robot (Intuitive Surgical ™, Sunnyvale, CA, USA), we were able to eliminate the large incision and use a much shorter nerve graft when performing contralateral C7 nerve transfer.

Nerve transfer in the management of upper extremity paralysis after brachial plexus and central neurologic injuries: Experience of Huashan

Huashan Hospital receives the largest population of brachial plexus injury patients in China. Here, we presented our latest follow-up cases and newest strategies of nerve transfer in different types of brachial plexus injury, including both supra- and infra-clavicular injuries. The most challenging brachial plexus avulsion injuries (BPAI) involving partial (upper/lower) or global plexus will be mainly discussed. We will focus on optimized combination of nerve transfer strategies for perusing the best outcomes, especially the distal functions. In partial brachial plexus injury patients, several intra-brachial plexus donor nerves are utilized, such as brachialis branch of the musculocutaneous nerve, superior motor branch of the median nerve, partial ipsilateral C7 nerve. The extended applications of contralateral C7 nerve transfer and full-length phrenic nerve transfer will be specifically introduced. Moreover, special brachial plexus injury types with non-classical nerve transfer surgery are also included. As the central nervous system plays an important part in the rehabilitation process of peripheral nerve injury, we further explored the relationship between brachial plexus injury-repair (transfer) and brain reorganization. Based on our previous researches, the contralateral C7 nerve transfer shows the capacity of inducing the compensation potential of the intact hemisphere after unilateral central neurologic injury (e.g. cerebral palsy, traumatic brain injury, stroke). The contralateral C7 nerve transfer was thus used in treating hemiplegic upper extremities and applied in more than 50 patients. The preliminary results of these cases will also be presented.

Donor-side morbidity after contralateral C-7 nerve transfer: results at a minimum of 6 months after surgery.

OBJECT Donor-side morbidity associated with contralateral C-7 (CC7) nerve transfer remains controversial. The purpose of this study was to evaluate functional deficits in the donor limb resulting from prespinal route CC7 nerve transfer. METHODS A total of 63 patients were included. Forty-one patients had undergone CC7 nerve transfer surgery at least 6 months previously and were assigned to one of 2 groups based on the duration of postoperative follow-up. Group 1 (n = 21) consisted of patients who had undergone surgery between 6 months and 2 years previously, and Group 2 (n = 20) consisted of patients who had undergone surgery more than 2 years previously. An additional 22 patients who underwent CC7 nerve transfer surgery later than those in Groups 1 and 2 were included as a control group (Group 3). Results of preoperative testing in these patients and postoperative testing in Groups 1 and 2 were compared. Testing included subjective assessments and objective examinations. An additional 3 patients had undergone surgery more than 6 months previously but had severe motor weakness and were therefore evaluated separately; these 3 patients were not included in any of the study groups. RESULTS The revised Short-Form McGill Pain Questionnaire (SF-MPQ-2) was the only subjective test that showed a significant difference between Group 3 and the other 2 groups, while no significant differences were found in objective sensory, motor, or dexterity outcomes. The interval from injury to surgery for patients with a normal SF-MPQ-2 score in Groups 1 and 2 was significantly less than for those with abnormal SF-MFQ-2 scores (2.4 ± 1.1 months vs 4.6 ± 2.9 months, p = 0.002). The 3 patients with obvious motor weakness showed a tendency to gradually recover. CONCLUSIONS Although some patients suffered from long-term sensory disturbances, resection of the C-7 nerve had little effect on the function of the donor limb. Shortening preoperative delay time can improve sensory recovery of the donor limb.

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

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

Contralateral C7 Nerve Transfer with Direct Coaptation to Restore Lower Trunk Function After Traumatic Brachial Plexus Avulsion Injuries: Surgical Technique

BJS Essential Surgical Techniques (JBJS EST) is the premier journal describing how to perform orthopaedic surgical procedures, verified by evidence-based outcomes, vetted by peer review, while utilizing online delivery, imagery and video to optimize the educational experience, thereby enhancing patient care. WHAT MAKES JBJS ESSENTIAL SURGICAL TECHNIQUES ESSENTIAL READING? Edited by Edward Cheng, MD, JBJS EST is an online journal for orthopaedic surgeons, from seasoned veterans to those just starting out in this field. It offers readers a continuously expanding online library of thoroughly vetted surgical procedures. Easy to Read, Easy to Absorb: Each surgical procedure is described step by step and illustrated extensively with images to encourage greater understanding of the procedure and concepts. Video excerpts are frequent features. Indications, contraindications, pitfalls, and challenges are clearly highlighted. Peer reviewed and derived from a top-quality published clinical article: Readers can be confident that these procedures are based on solid scientific concepts, because all articles contain outcomes that have been reported on in previously published peer-reviewed publications. JBJS EST articles are subjected to the same rigorous editorial, peer-review, and copyediting process that has established The Journal of Bone & Joint Surgery's reputation for excellence. Contributions to JBJS EST are welcomed from anywhere in the world and are considered on their merits. Articles must be written in English and should be submitted as outlined in the Instructions to Authors. All authors must abide by the JBJS Ethics Policies.

Contralateral C7 Nerve Transfer with Direct Coaptation to Restore Lower Trunk Function After Traumatic Brachial Plexus Avulsion Injuries: Surgical Technique.

We describe a new technique for treating traumatic brachial plexus avulsion injury with a contralateral C7 nerve transfer with direct coaptation that shortens the time to muscle reinnervation. Explore the brachial plexus carefully and confirm the nerve-root avulsion injuries from C7 to T1. Dissect the divisions of the contralateral C7 nerve root, divide the nerve at the junction between the divisions and cords, and mobilize it proximally. Create the prespinal route to guide the contralateral C7 nerve to the injured side. If the contralateral C7 nerve does not reach the injured lower trunk, perform a humeral shortening osteotomy, generally with <5 cm of shortening in adults. Suture one end of the sural nerve together with the medial antebrachial cutaneous nerve to the musculocutaneous nerve; anastomose the remainder of the contralateral C7 nerve directly with the lower trunk. Use a prefabricated brace to hold the head in the neutral position and immobilize the injured limb for six weeks. We evaluated the results of the technique in a study of seventy men and five women with a mean age (and standard deviation) of 28 ± 10 years (range, ten to fifty-three years).IndicationsContraindicationsPitfalls & Challenges.

Branches of the lower trunk neurotized by pre-vertebral route contralateral C7 nerve transfer as donor nerves: a preliminary study

Objective To explore the feasibility and effectiveness of using branches of the lower trunk on the affected side as donor nerves,i.e.medial brachial cutaneous nerve,medial antebrachial cutaneous nerve and posterior division of the lower trunk,after contralateral C7 nerve root transfer to the lower trunk via pre-vertebral route.Methods When the phrenic nerve and spinal accessory nerve were injured along with the brachial plexus,contralateral C7 nerve root was transferred to repair the lower trunk via pre-vertebral toute.Medial antebrachial cutaneous nerve of the affected side was again transferred to repair the musculocutaneous nerve,medial brachial cutaneous nerve transferred to repair the suprascapular nerve,posterior division of the lower trunk transferred to repair lateral head of the median nerve.A total of 14 cases of complete brachial plexus root avulsions were treated.Results Postoperatively 12 cases were follow-up for 24 to 65 months (mean,35 months).Average shoulder abduction reached 39°.Results in 67％ of the cases were considered effective (musele strength reached M2),and 58 ％ excellent (muscle strength reached M3).The average angle of elbow flexion was 77°,75％ rated effective and 58％ rated excellent.Finger and thumb flexion was restored to some extent.Finger flexor strength was ≥ M2 in 7 cases with an effective rate of 58 ％ and ≥ M3 in 5 cases with an excellent rate of 42％.Conclusion After being neurotized by the contralateral C7 nerve root via pre-vertebral route,branches of the lower trunk can be used as donor nerves to neurotize the musculocutaneous nerve,supraseapular nerve and lateral head of the median nerve. Key words: Brachial plexus; Nerve transfer; Microsurgery; Hand

Contralateral C7 Nerve Transfer with Direct Coaptation to Restore Lower Trunk Function After Traumatic Brachial Plexus Avulsion

Contralateral C7 nerve transfer to the median nerve has been used in an attempt to restore finger flexion in patients with total brachial plexus avulsion injury. However, the results have not been satisfactory mainly because of the requirement to use a long bridging nerve graft, which causes an extended nerve regeneration process and irreversible muscle atrophy. A new procedure involving contralateral C7 nerve transfer via a modified prespinal route and direct coaptation with the injured lower trunk is presented here. Contralateral C7 nerve transfer via the modified prespinal route and direct coaptation with the injured lower trunk was performed in seventy-five patients with total brachial plexus avulsion injury. Thirty-five required humeral shortening osteotomy (3 to 4.5 cm) in order to accomplish the direct coaptation. The contralateral C7 nerve was also transferred to the musculocutaneous nerve through the bridging medial antebrachial cutaneous nerve arising from the lower trunk in forty-seven of the seventy-five patients. Recovery of finger, wrist, and elbow flexion was evaluated with use of the modified British Medical Research Council muscle grading system. The mean follow-up period (and standard deviation) was 57 ± 6 months (range, forty-eight to seventy-eight months). Motor function with a grade of M3+ or greater was attained in 60% of the patients for elbow flexion, 64% of the patients for finger flexion, 53% of the patients for thumb flexion, and 72% of the patients for wrist flexion. Contralateral C7 nerve transfer via a modified prespinal route and direct coaptation with the injured lower trunk decreases the distance for nerve regeneration in patients with total brachial plexus avulsion injury. There was satisfactory recovery of finger flexion and wrist flexion in this series. In addition, contralateral C7 nerve transfer was successfully used to repair two different target nerves: the lower trunk and the musculocutaneous nerve.

The Effectiveness of Contralateral C7 Nerve Root Transfer for the Repair of Avulsed C7 Nerve Root in Total Brachial Plexus Injury: An Experimental Study in Rats

The aim of this study was to evaluate the feasibility and effectiveness of transferring the contralateral C7 root to repair avulsed C7 nerve root. Thirty rats were randomized into three groups. In group A, rats underwent whole-root avulsion of the left brachial plexus and contralateral C7 root transfer to the avulsed C7 nerve root. In group B, rats underwent whole-root avulsion and contralateral C7 root transfer to the radial nerve. In group C, rats underwent whole-root avulsion of the left brachial plexus without nerve transfer. Functional outcomes were measured by electrophysiological studies, muscle tetanus contraction force, muscle mass, and histology. Six months postoperatively, increased amplitude and shortened latency of compound muscle action potentials, larger maximum tetanic contractile tension, heavier muscle mass, and larger cross-sectional area of the muscle fibers were observed in the triceps, extensor carpi radialis brevis, and extensor digitorum in groups A and B when compared with group C (p < 0.01). There were no significant differences between group A and B (p > 0.05). Contralateral C7 nerve transfer to repair avulsed C7 nerve root was feasible and effective in this rat model. It should be considered as an option for the treatment of brachial plexus injuries.

Transhemispheric Cortical Plasticity Following Contralateral C7 Nerve Transfer: A Rat Functional Magnetic Resonance Imaging Survival Study

To perform contralateral C7 nerve transfer in a controlled, survival rat functional magnetic resonance imaging model, so as to understand the extent of cortical plasticity after brachial plexus injury and surgical manipulation with this procedure. A total of 24 rats divided into 3 groups underwent surgery followed by functional magnetic resonance imaging in this study. Group I rats served as sham controls. Group II injury rats underwent complete right brachial plexus root avulsion. Group III repair rats underwent complete right brachial plexus root avulsion and then contralateral C7 nerve transfer to the right median nerve. We assessed cortical response to median nerve stimulation at 0, 3, and 5 months after injury using functional magnetic resonance imaging at 9.4 T. We concurrently performed sensory and motor functional testing. We noted a progression in cortical activation in the repair rats over 0, 3, and 5 months. Initially, right median nerve stimulation in the repair group showed complete loss of activation in the contralateral somatosensory cortex. Nerve stimulation at 3 months produced primarily ipsilateral cortical activation; at 5 months, 3 patterns of cortical activation emerged: ipsilateral, bilateral, and contralateral activation. After right median nerve stimulation, injury rats maintained a lack of cortical activation and control rats maintained exclusive contralateral activation throughout all time points. Functional testing revealed a degree of return of sensory and motor function over time in the repair group compared with the injured group. A high degree of transhemispheric cortical plasticity occurred after contralateral C7 nerve transfer. There appears to be a predilection for the rat brain to restore the preinjury somatotopic representation of the brain. Understanding the cortical changes after nerve injury and repair may lead to specific pharmacologic or behavioral interventions that can improve functional outcomes.