Contralateral C7 Nerve Transfer Research Articles

Anatomical study of single incision contralateral C7 nerve transfer through subdural pathway.

To explore the feasibility of single incision C7 nerve transfer surgery through the subarachnoid pathway on the healthy side through anatomical research. Four fresh frozen cadaver specimens were used for the study. Observe and measure the length of C7 nerve root fibers. Divide the front root into 3 bundles and the rear root into 5 bundles. The C7 nerve has a filamentous structure, arranged symmetrically on both sides, and the length of the root fibers gradually shortens from top to bottom. The length of the left anterior root decreased from (12.25 ± 0.68) mm to (9.75 ± 1.40) mm, the length of the right anterior root decreased from (12.95 ± 1.49) mm to (10.00 ± 2.00) mm, the length of the left posterior root decreased from (15.63 ± 1.55) mm to (12.38 ± 0.71) mm, and the length of the right posterior root decreased from (15.48 ± 1.37) mm to (12.30 ± 0.90) mm. The distance from the exit of the C7 nerve from the dura mater to the fusion site in 4 specimens was (10.98 ± 1.21) mm on the left and (10.98 ± 1.391) mm on the right. All four specimens have completed nerve bundle anastomosis. From an anatomical perspective, it is feasible to anastomose the healthy side C7 nerve with the affected side root fibers in the dorsal bundle of the spinal cord after cutting off the dura mater.

Cadaveric Feasibility Study on Modified Contralateral C7 Nerve Transfer for Targeted Recovery in Hemiplegic Arms.

Contralateral cervical seventh (cC7) nerve to C7 transfer has been proven effective for treating spastic upper limb. However, for those whose major impairment is not in the C7 area, cC7 nerve transfer to other nerves may achieve a better outcome. The aim of this study was to explore the optimal surgical approach for transferring cC7 to 1 or 2 nerves in a cadaveric study, and to evaluate possible applications for patients with hemiplegia. Modified cC7 transfer to 1 (5 procedures) or 2 nonadjacent (3 procedures) nerve roots was proposed, and success rates of direct coaptation through 2 surgical approaches-the superficial surface of longus colli (sLC) and the deep surface of longus colli (dLC) approach-were compared. The length, diameter, and distance of relevant nerves were also measured in 25 cadavers. Compared with the sLC approach, the distance of the dLC approach was 1.1 ± 0.3 cm shorter. The success rates for the sLC and dLC approaches were as follows: cC7 to C5 surgery, 94%, and reached 98%; cC7 to C6 surgery, 54% and 96%; cC7 to C7 surgery, 42% and 94%; cC7 to C8 surgery, 34% and 94%; cC7 to T1 surgery, 24% and 62%; cC7 to C5C7 surgery, 74% and 98%; cC7 to C6C8 surgery, 54% and 98%; and cC7 to C7T1 surgery, 42% and 88%. The dLC approach greatly improved the direct coaptation rate for cC7 nerve transfer. The modified cC7 nerve transfer procedures are technically feasible for further application in clinic.

A Colombian's Group Experience Using Contralateral C7 Nerve Transfer for Brachial Plexus Trauma

A Colombian's Group Experience Using Contralateral C7 Nerve Transfer for Brachial Plexus Trauma

Contralateral seventh cervical nerve transfer for central spastic arm paralysis: a systematic review and meta-analysis.

The specific benefits of a contralateral cervical 7 nerve transplant in people with spastic paralysis of the upper extremity caused by cerebral nerve injury are unclear. To evaluate the efficacy and safety of contralateral C7 nerve transfer for central spastic paralysis of the upper extremity, we conducted a comprehensive literature search and meta-analysis. PRISMA guidelines were used to search the databases for papers comparing the efficacy of contralateral cervical 7 nerve transfer vs. rehabilitation treatment from January 2010 to August 2022. The finishing indications were expressed using SMD ± mean. A meta-analysis was used to assess the recovery of motor function in the paralyzed upper extremity. The meta-analysis included three publications. One of the publications offers information about RCTs and non-RCTs. A total of 384 paralyzed patients were included, including 192 who underwent CC7 transfer and 192 who received rehabilitation. Results from all patients were combined and revealed that patients who had CC7 transfer may have regained greater motor function in the Fugl-Meyer score (SMD 3.52, 95% CI = 3.19-3.84, p < 0.00001) and had superior improvement in range of motion compared to the rehabilitation group (SMD 2.88, 95% CI = 2.47-3.29, p < 0.00001). In addition, the spasticity in the paralyzed upper extremity significantly improved in patients with CC7 transfer (SMD -1.42, 95% CI = -1.60 to -1.25, p < 0.00001). Our findings suggested that a contralateral C7 nerve transfer, which has no additional adverse effects on the healthy upper limb, is a preferable method to restore motor function.

Impact of Severe Cervical Foraminal Stenosis on Contralateral C7 Nerve Transfer Outcomes

This report presents the case of a 67-year-old male patient with severe bilateral C6/7 foraminal stenoses who underwent contralateral seventh cervical nerve (C7) transfer as a treatment for left spastic hemiparesis resulting from a right middle cerebral artery infarction. The initial postoperative results showed improved spasticity and motor function, but these gains plateaued and even receded, unlike other studies that noted progress at 10–18 months post-surgery. We hypothesized that the presence of C7 radiculopathy due to severe cervical foraminal stenosis may affect long-term outcomes after contralateral C7 transfer and serve as a contraindication for this surgery. These findings emphasize the importance of thoroughly assessing patients with cervical foraminal stenosis and the associated risk of radiculopathy before considering a contralateral C7 transfer. Further research is needed to assess the prevalence of cervical foraminal stenosis in patients undergoing contralateral C7 transfer and explore alternative surgical approaches or adjunctive treatments to optimize postoperative outcomes.

Current strategies of the brachial plexus palsy management

The importance of brachial plexus palsy treatment is associated with its significant severity, along with Brachial plexus palsies can be treated by means of many different surgical and non-surgical methods which allow regeneration of full efficiency of the affected limb. The choice of method depends on such factors as type and region of injury, patient’s age or clinical presentation of the injury. The purpose of this review is to present current strategies of treating brachial plexus palsies, depending on therapeutic needs of the particular patient. This is a review study based upon selective literature overview, with emphasis on works published within past 13 years. 6 separate methods of brachial plexus palsy were assessed, without distinction of the reason of palsy occurring. Some of the invasive methods include operative treatment performed directly on occupied nervous tissue, such as microneural plexus reconstruction and nerve transfers (lower subscapular nerve transfer and contralateral C7 nerve transfer) whilst the others revolve around restoration of function of affected neighboring structures by themselves, e.g. shoulder tendon transfers. Rehabilitation and botulinum toxin-based treatment are non-operative methods revolving around enhancement of the function of the affected upper limb. Main measure of effectiveness of the treatment is assessment of the range of motion of the affected limb (ROM). There is still not enough information available regarding long-term efficiency of microneural plexus reconstruction and botulinum toxin-based treatment. They require further investigation while other methods are used commonly.

Contralateral C7 nerve transfer for severe pediatric brachial plexus injuries: donor site morbidity.

Pediatric brachial plexus injuries (BPI) can have a devastating impact on upper extremity function. With localized lesions, nerve grafting and transfers are well-described. However, reconstruction of pan-plexus (C5-T1) injuries (PPI) requires donor nerves outside of the brachial plexus. The cross C7 (CC7) nerve transfer extended with sural nerve grafts to the contralateral recipient nerve offers the advantage of supplying robust donor axons. Though controversial in the West, CC7 transfer is routine in many Asian centers. We present a case series of pediatric patients who underwent CC7 transfer for BPI. Our objective was to catalog donor site morbidity incurred by transferring the C7 nerve root. This retrospective study was approved by the Institutional Review Board of our university. patients under 18years old that underwent CC7 nerve transfer for BPI at our health system between 2021 and 2022. A chart review was completed to collect demographic and outcomes data. Three patients underwent a complete CC7 transfer between 2021 and 2022 for BPI reconstruction. All patients underwent concomitant additional nerve transfers. Post-operative donor site sensory deficits were minimal and transient in all but one patient, who reported mild but persistent paresthesia of the donor side hand with movement of recipient side digits; however, no patients suffered donor site motor deficits (Table 1). We conclude that CC7 nerve transfer is a safe surgical option to provide additional donor motor axons for PPI in pediatric patients.

MRI-Based Optimization Design of the Pre-Spinal Route of Contralateral C7 Nerve Transfer for Spastic Arm Paralysis.

PurposeThe prespinal route of contralateral cervical 7 nerve transfer developed by Prof. Wendong Xu helps realize the direct anastomosis of the bilateral cervical 7 nerves. However, 20% of operations still require a nerve graft, which leads to an unfavorable prognosis. This study aims to explore the optimized prespinal route with MRI to further improve the prognosis.MethodsThe current study enrolled 30 patients who suffered from central spastic paralysis of an upper limb and who underwent contralateral cervical 7 nerve transfer via Prof. Xu’s prespinal route through the anterior edge of the contralateral longus colli. MRI images were used to analyze the route length, vertebral artery exposure, and contralateral cervical 7 nerve included angle. Three prespinal routes were virtually designed and analyzed. The selected optimal route was applied to another 50 patients with central spastic paralysis of an upper limb for contralateral cervical 7 nerve transfer.ResultsBy the interventions on the 30 patients, the middle and posterior routes were shorter than the anterior route in length, but with no statistical difference between the two routes. Of 30 contralateral vertebral arteries, 26 were located at the posterior medial edge of the longus colli. The average included angles of the anterior, middle, and posterior routes were 108.02 ± 7.89°, 95.51 ± 6.52°, and 72.48 ± 4.65°, respectively. According to these data, the middle route was optimally applied to 50 patients, in whom the rate of nerve transplantation was only 4%, and no serious complications such as vertebral artery or brachial plexus injury occurred.ConclusionThe low rate of nerve transplantation in 50 patients and the absence of any serious complications in these cases suggests that the middle route is the optimal one.

Functional outcome of contralateral C7 nerve transfer combined with free functional gracilis transplantation to repair total brachial plexus avulsion: a report of thirty-nine cases

PurposeTreatment of total brachial plexus avulsion (TBPA) is a challenge in the clinic, especially the restoration of hand function. The current main surgical order is from proximal to distal joints. The purpose of this study was to demonstrate the outcomes of “distal to proximal” surgical method.MethodsThirty-nine patients underwent contralateral C7 (CC7) nerve transfer to directly repair the lower trunk (CC7-LT) and phrenic nerve transfer to the suprascapular nerve (PN-SSN) during the first stage, followed by free functional gracilis transplantation (FFGT) for elbow flexion and finger extension. Muscle strength of upper limb, degree of shoulder abduction and elbow flexion, and Semmes–Weinstein monofilament test and static two-point discrimination of the hand were examined according to the modified British Medical Research Council (mBMRC) scoring system.ResultsThe results showed that motor recovery reached a level of M3 + or greater in 66.7% of patients for shoulder abduction, 87.2% of patients for elbow flexion, 48.7% of patients for finger extension, and 25.6% of patients for finger flexion. The mean shoulder abduction angle was 45.5° (range 0–90°), and the average elbow flexion angle was 107.2° (range 0–142°), with 2.5 kg average flexion strength (range 0.5–5 kg). In addition, protective sensibility (≥ S2) was found to be achieved in 71.8% of patients.ConclusionIn reconstruction of TBPA, CC7 transfer combined with free functional gracilis transplantation is an available treatment method. It could help patients regain shoulder joint stability and the function of elbow flexion and finger extension and, more importantly, provide finger sensation and partial finger flexion function. However, the pick-up function was unsatisfied, which needed additional surgery.

A new approach for contralateral C7 nerve transfer via retrospinal route

Anterior and posterior approaches exist for the treatment of spinal pathologies. Anatomically, the 7th cervical spinal nerve(C7)crosses the C6-C7 intervertebral foramen bilaterally, allowing contralateral prevertebral or posterior C7 nerve transfer to be used. The advantage of the posterior rather than the anterior spinal approach is that it does not require retraction of important blood vessels, nerves, or other structures. In this paper, we describe transfer of the contralateral C7 nerve using a posterior approach.

Contralateral C7 nerve transfer in the treatment of upper-extremity paralysis: a review of anatomical basis, surgical approaches, and neurobiological mechanisms.

The previous three decades have witnessed a prosperity of contralateral C7 nerve (CC7) transfer in the treatment of upper-extremity paralysis induced by both brachial plexus avulsion injury and central hemiplegia. From the initial subcutaneous route to the pre-spinal route and the newly-established post-spinal route, this surgical operation underwent a series of innovations and refinements, with the aim of shortening the regeneration distance and even achieving direct neurorrhaphy. Apart from surgical efforts for better peripheral nerve regeneration, brain involvement in functional improvements after CC7 transfer also stimulated scientific interest. This review summarizes recent advances of CC7 transfer in the treatment of upper-extremity paralysis of both peripheral and central causes, which covers the neuroanatomical basis, the evolution of surgical approach, and central mechanisms. In addition, motor cortex stimulation is discussed as a viable rehabilitation treatment in boosting functional recovery after CC7 transfer. This knowledge will be beneficial towards improving clinical effects of CC7 transfer.

Contralateral C7 Nerve Transfer for Stroke Recovery: New Frontier for Peripheral Nerve Surgery.

Ischemic stroke remains a major cause of disability in the United States and worldwide. Following the large-scale implementation of stroke thrombectomy and the optimization of treatment protocols for acute stroke, the reduction in stroke-associated mortality has resulted in an increased proportion of stroke survivors, many of whom have moderate to severe disability. To date, the treatment of subacute and chronic stroke has remained a challenge. Several approaches, involving pharmacological interventions to promote neuroplasticity, brain stimulation strategies and rehabilitative interventions, are currently being explored at different stages of the translational spectrum, yet level 1 evidence is still limited. In a recent landmark study, surgical intervention using contralateral C7 nerve transfer, an approach used to treat brachial plexus injury, was implemented in patients with chronic stroke, demonstrating an added benefit to standard rehabilitation strategies, leading to improved motor performance and reduced spasticity. The procedure involved the transfer of the C7 nerve root and middle trunk from the uninjured extremity to the injured extremity using a short conduit that allows for faster regeneration and innervation of the injured upper extremity via the ipsilateral (contralesional) hemisphere. In this work, we review the rationale for using contralateral C7 nerve transfer in stroke, describe the surgical intervention with associated variations and limitations, and discuss the current evidence for the efficacy of this technique in ischemic stroke research.

Clinical Anatomy of Human Donor C7 Nerve Roots for Surgical Transfer in Patients with Spastic Arm Paralysis

Contralateral C7 (CC7) nerve transfer has successfully restored hand function in patients with spastic hemiplegia from chronic central nervous system injuries. However, little is known about the morphology and anatomy of the donor C7 nerve root in patients undergoing this procedure. This study quantified intraoperative measurements of donor C7 nerve roots during CC7 transfer surgery for spastic hemiplegia in patients treated at a high-volume center to describe observed anatomical variations for successful direct anastomosis. A database of images from 21 patients (2 females, 19 males) undergoing CC7 surgery was searched for photographic data that contained a standard ruler measuring donor C7 nerve root length after surgical sectioning and before transfer. Two independent observers analyzed these images and recorded C7 nerve root diameter, length, and branch lengths. Mean (SD) values of donor C7 nerve measurements were length, 53.5 (8.0) mm; diameter, 5.1 (0.9) mm; branch length following surgical sectioning, 18.3 (6.3) mm. Right-sided donor C7 nerve roots yielded significantly longer branches compared with left-sided donor C7 nerve roots (P= 0.01). Other patient factors such as age, sex, or laterality of brain injury did not influence intraoperative anatomy. We report detailed intraoperative measurements of the donor C7 root during CC7 nerve transfer for spastic hemiplegia. These findings describe existing variation in surgical C7 nerve root anatomy in patients undergoing this procedure and may serve as a general reference for the expected donor C7 length in successful direct anastomosis.

Aberrant central plasticity underlying synchronous sensory phenomena in brachial plexus injuries after contralateral cervical seventh nerve transfer.

BackgroundsContralateral cervical seventh (C7) nerve transfer aids motor and sensory recovery in total brachial plexus avulsion injuries (TBPI), but synchronous sensation often persists postoperatively. The mechanism underlying synchronous sensory phenomena remain largely unknown.ObjectiveTo investigate the role of central plasticity in sensory recovery after contralateral C7 nerve transfer.MethodsSixteen right TBPI patients who received contralateral C7 nerve transfer for more than 2 years were included. Sensory evaluations included Semmes–Weinstein monofilament assessment (SWM), synchronous sensation test, and sensory evoked action potential (SNAP) test. Smaller value in the SWM assessment and larger amplitude of SNAP indicates better tactile sensory. Functional magnetic resonance imaging was performed while stimulations delivered to each hand separately in block‐design trials for central plasticity analysis.ResultsThe SWM value of the injured right hand was increased compared with the healthy left side (difference: 1.76, 95% confidence interval: 1.37–2.15, p < .001), and all 16 patients developed synchronous sensation. In functional magnetic resonance imaging analysis, sensory representative areas of the injured right hand were located in its ipsilateral S1, and 23.4% of this area overlapped with the representative area of the left hand. The ratio of overlap for each patient was significantly correlated with SWM value and SNAP amplitude of the right hand.ConclusionThe tactile sensory functioning of the injured hand was dominated by its ipsilateral SI in long‐term observation, and its representative area largely overlapped with the representative area of the intact hand, which possibly reflected a key mechanism of synchronous sensation in patients with TBPI after contralateral C7 transfer.

Why It Is Necessary to Use the Entire Root rather than Partial Root When Doing Contralateral C7 Nerve Transfer: Cortical Plasticity Also Matters besides the Amount of Nerve Fibers.

Previous studies suggested that the mode of donor transection is a critical factor affecting the efficacy of the contralateral C7 (CC7) nerve transfer. Nevertheless, the mechanism underlying this phenomenon remains elusive. The aim of this study was to investigate the relationship between the division modes of the CC7 nerve and cortical functional reorganization of Sprague-Dawley rats. We hypothesized that different methods of CC7 nerve transection might induce differences in cortical functional reorganization, thus resulting in differences in surgery efficacy. BDNF, TNF-α/IL-6, and miR-132/134 were selected as indicators of cortical functional reorganization. No significant differences in all these indicators were noted between the entire group and the entire root+posterior division group (P > 0.05). BDNF and miR-132/134 levels in the entire group and the entire root+posterior division group were significantly increased compared with their levels in the posterior group and the blank control group (P < 0.001). In all groups, BDNF, TNF-α/IL-6, and miR-132/134 levels in both hemispheres initially increased and subsequently decreased until week 40. In conclusion, this study provided the evidence of dynamic changes in BDNF, TNF-α/IL-6, and miR-132/134 in the cortex of rats after CC7 nerve transfer using different transecting modes, demonstrating that different CC7 nerve divisions might result in different surgical effects through modulation of cortical reorganization.

Contralateral cervical seventh nerve transfer for spastic arm paralysis via a modified prespinal route: a cadaveric study.

We proposed contralateral cervical seventh nerve transfer for spastic arm paralysis after central neurological injury in the New England Journal of Medicine (NEJM) in 2018. In this surgery, we applied a new surgical route for nerve transfer, the Huashan prespinal route. The objective of this study was to elaborate our new surgical technique, clarify its relationship to the vertebral artery, and provide anatomical data on this novel method. The effectiveness and safety of the Huashan prespinal route in contralateral C7 nerve transfer were evaluated anatomically. Nine cadavers (4 males, 5 females) were available for this study. Among these, anatomical parameters of the vertebral artery were obtained from 6 cadavers, and the anastomosis of the bilateral cervical seventh nerve was observed on 3 cadavers undergoing contralateral C7 nerve transfer via the Huashan prespinal route. Tension-free anastomosis of the bilateral cervical seventh nerve was achieved through the Huashan prespinal route. The tilt angle of the vertebral artery to the sagittal plane (with thyroid cartilage as the origin) was 25.5 ± 4.5°, at 22.5 ± 1.6° and 28.7 ± 4.3° on the left and right side, respectively. The safe drilling angle to penetrate through the longus colli muscles for the creation of a longus colli muscle tunnel to avoid injury to the vertebral artery in our surgical technique was above 33.2°. The cadaveric study confirms that the presented technique allowed simple, effective, and safe contralateral C7 nerve transfer. This technique can be used in the treatment of hemiplegia and brachial plexus injury. There is a safe scope of drilling angle for creating the longus colli muscle tunnel required for this surgical route. The anatomical parameters obtained in this study will be helpful for the performance of this operation.

Letter to the Editor Regarding “Treatment of Central Paralysis of Upper Extremity Using Contralateral C7 Nerve Transfer via Posterior Spinal Route”

Letter to the Editor Regarding “Treatment of Central Paralysis of Upper Extremity Using Contralateral C7 Nerve Transfer via Posterior Spinal Route”

Experiment study of the miR-124 and miR-138 expression in rat primary motor cortex during the trans-hemispheric functional reorganization after the contralateral C7 nerve transfer

Objective To investigate the role of miR-124 and miR-138 in regulating the brain trans-hemispheric functional reorganization after the contralateral C7 transfer. Methods According to the model establishment and surgical treatment, 126 male SD rats were divided randomly into three groups: operation group, simple avulsion group and sham group. In the operation group, the right total brachial plexus avulsion model was made and the left C7 nerve root was cut as a donor to repair the right median nerve through ulnar nerve bridging. In the simple avulsion group, only the right total brachial plexus avulsion model was made and the left brachial plexus was only exposed. The sham group only exposed the bilateral brachial plexus. RT-PCR was used to detect the expression of miR-124 and miR-138 in bilateral brain motor cortex of rats at different time points after operation, and the correlation was analyzed. Results The expression level of miR-124 and miR-138 in the operation group and simple avulsion group showed dynamic changes with time, while in the sham group they showed no significant difference between different time points. The expression level of miR-124 and miR-138 in the operation group were greater than those in the simple avulsion group, and those in the simple avulsion group was higher than those in the sham operation group (P 0.05). The expression levels of miR-124 and miR-138 in the left hemisphere of the simple avulsion group were significantly higher than those in the right hemisphere (P<0.05). Conclusion The miR-124 and miR-138 may be invovled in the regulation of brain function remodeling after the contralateral C7 nerve transfer. Key words: Brachial plexus; Animal experimentation; Contralateral C7 nerve transfer; miRNA

Application of CUBE-STIR MRI and high-frequency ultrasound in contralateral cervical 7 nerve transfer surgery

Objective The objective of the study was to investigate the feasibility of CUBE-SITR MRI and high-frequency ultrasound for the structural imaging of the brachial plexus to exclude neoplastic brachial plexopathy or structural variation and measure the lengths of anterior and posterior divisions of the C7 nerve, providing guidelines for surgeons before contralateral cervical 7 nerve transfer. Methods A total of 30 patients with CNS and 20 with brachial plexus injury were enrolled in this retrospective study. All patients underwent brachial plexus CUBE-STIR MRI and high-frequency ultrasound, and the lengths of the anterior and posterior divisions of C7 nerve were measured before surgery. Precise length of anterior and posterior divisions of contralateral C7 nerve was measured during surgery. Results MRI-measured lengths of anterior and posterior divisions of C7 nerves were positively correlated with that measured during surgery (anterior division, r = 0.94, p < .01; posterior division, r = 0.92, p < .01). High agreement was found between MRI-measured and intra-surgery measured length of anterior and posterior divisions of C7 nerve by BLAD-ALTMAN analysis. Ultrasonography could feasibly image supraclavicular C7 nerve and recognize small variant branches derived from middle trunk of C7 nerve root, which could be dissected intra-operatively and confirmed by electromyography during the procedure of contralateral C7 nerve transfer. Conclusion CUBE-STIR MRI had advantages for the imaging of the brachial plexus and measurement of the length of root-trunk-anterior/posterior divisions of C7 nerve. The clinical role of ultrasonography may be a simple way of evaluating general condition of C7 nerve and provide guidelines for contralateral C7 nerve transfer surgery.

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.