Mou-Xiong Zheng

Phrenic Nerve Transfer for Elbow Flexion and Intercostal Nerve Transfer for Elbow Extension

PURPOSE To explore long-term recovery of elbow flexion and extension after transferring the phrenic nerve and intercostal nerves, respectively, in adults with global brachial plexus avulsion injuries. METHODS Seven adults with global brachial plexus avulsion injuries had the phrenic nerve transferred to the musculocutaneous nerve (or to the anterior division of upper trunk) and intercostal nerves transferred to the triceps branch of the radial nerve at our hospital 7 to 12 years ago. The results of elbow motor strength testing using the Medical Research Council grading scale, and electrodiagnostic findings using electromyogram examinations, were studied retrospectively. Pulmonary function tests were also performed at final visits. RESULTS Functional elbow flexion was obtained in most of the 7 cases (M2, 1; M3, 3; M4, 2; and M5, 1) but elbow extension was absent or insufficient in all subjects (M0, 1; M1, 3; and M2, 3). Electrical results showed successful biceps reinnervation in 6 patients and successful triceps reinnervation in 5. No patient experienced breathing problems, and pulmonary function results were within normal range. CONCLUSIONS In the long term, after brachial plexus avulsion injury in most patients who underwent both phrenic nerve and intercostal nerve transfer to achieve elbow flexion and extension eventually obtained satisfactory elbow flexion but poor elbow extension. We recommend against transferring the intercostal nerves to the triceps branch of radial nerve in conjunction with primary phrenic to musculocutaneous nerve transfer. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic IV.

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.

Trial of Contralateral Seventh Cervical Nerve Transfer for Spastic Arm Paralysis

BACKGROUND Spastic limb paralysis due to injury to a cerebral hemisphere can cause long‐term disability. We investigated the effect of grafting the contralateral C7 nerve from the nonparalyzed side to the paralyzed side in patients with spastic arm paralysis due to chronic cerebral injury. METHODS We randomly assigned 36 patients who had had unilateral arm paralysis for more than 5 years to undergo C7 nerve transfer plus rehabilitation (18 patients) or to undergo rehabilitation alone (18 patients). The primary outcome was the change from baseline to month 12 in the total score on the Fugl–Meyer upper‐extremity scale (scores range from 0 to 66, with higher scores indicating better function). RESULTS The mean increase in Fugl–Meyer score in the paralyzed arm was 17.7 in the surgery group and 2.6 in the control group (difference, 15.1; 95% confidence interval, 12.2 to 17.9; P<0.001). With regard to improvements in spasticity as measured on the Modified Ashworth Scale (an assessment of five joints, each scored from 0 to 5, with higher scores indicating more spasticity), the smallest between‐group difference was in the thumb, with 6, 9, and 3 patients in the surgery group having a 2‐unit improvement, a 1‐unit improvement, or no change, respectively, as compared with 1, 6, and 7 patients in the control group (P=0.02). Transcranial magnetic stimulation and functional imaging showed connectivity between the ipsilateral hemisphere and the paralyzed arm. There were no significant differences from baseline to month 12 in power, tactile threshold, or two‐point discrimination in the hand on the side of the donor graft. CONCLUSIONS In this single‐center trial involving patients who had had unilateral arm paralysis due to chronic cerebral injury for more than 5 years, transfer of the C7 nerve from the nonparalyzed side to the side of the arm that was paralyzed was associated with a greater improvement in function and reduction of spasticity than rehabilitation alone over a period of 12 months. Physiological connectivity developed between the ipsilateral cerebral hemisphere and the paralyzed hand. (Funded by the National Natural Science Foundation of China and others; Chinese Clinical Trial Registry number, 13004466.)

Long-term observation of respiratory function after unilateral phrenic nerve and multiple intercostal nerve transfer for avulsed brachial plexus injury.

BACKGROUND: Phrenic nerve transfer (PNT) or multiple intercostal nerve transfer (MIT) alone are reported to have no significant impact on pulmonary function in the short or medium term, but it has rarely been reported whether the combination of PNT-MIT could influence respiratory function in the long term. OBJECTIVE: Respiratory function was evaluated after PNT and PNT-MIT 7 to 19 years (mean, 10 years) postoperatively. METHODS: Twenty-three adult patients with brachial plexus avulsion injuries who underwent PNT-MIT were compared with 19 corresponding patients who underwent PNT. Pulmonary function testings, phrenic nerve conduction study, and chest fluoroscopy were performed. In the PNT-MIT group, further investigation was performed on the effect of the number of transferred intercostal nerves and the timing of MIT. RESULTS: In the PNT-MIT group, forced vital capacity, forced expiratory volume in one second, and total lung capacity were 73.69%, 72.04%, and 74.81% of predicted values without significant differences from the PNT group. Diaphragmatic paralysis permanently existed with 1 to 1.5 intercostal spaces (ICSs) elevation and near 1 ICS reduced excursion. There was no statistical difference between the PNT and PNT-MIT groups. Furthermore, 3 and 4 intercostal nerves transferred resulted in no further decrease in pulmonary function test results than 2 intercostal nerves. No significant difference was found when PNT and MIT were performed at the same stage or with an interval. CONCLUSION: PNT-MIT did not result in additional impairment in respiratory function in adult patients compared with PNT alone. It is safe to transfer 2 to 4 intercostal nerves at 1 to 2 months delay after PNT.

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.

Interhemispheric functional reorganization after cross nerve transfer: via cortical or subcortical connectivity?

It has been demonstrated that there could be long range interhemispheric reorganization between bilateral hemispheres after peripheral cross nerve transfer. Our previous studies found a striking dynamic process of interhemispheric functional reorganization in adult rats with cross seventh cervical nerve transfer. But it remains a question whether the extensive interhemispheric functional reorganization after cross nerve transfer depends on connectivities at the cortical or subcortical level. In the present study, 18 rats with cross C7 transfer were concurrently treated with corpus callosotomy while the other 18 were not. Intracortical microstimulation was performed in the primary motor cortex (M1) at intervals of 5, 7, and 10 months postoperatively. The neural electrophysiology study showed that the representation of the injured forepaw appeared in the ipsilateral cortex at 5 months after the cross nerve transfer combined with corpus callosotomy, and it shared great overlapping zones with the representation of the health forepaw. And then, at 7-10 months, the cortical representation of the paralyzed forepaw was still located in the ipsilateral motor cortex, although significantly contracted. In contrast, rats with mere cross nerve transfer still presented interhemispheric reorganization. The results indicated that corpus callosotomy in the early stage after cross C7 transfer may had interrupted the interhemispheric functional reorganization. Combined the present study with our previous research findings, we explored the possible pathway and mechanisms of the interhemispheric functional reorganization. Thus we came to the conclusion that interhemispheric connectivity at the cortical level was essential in establishing the new contralateral control of the paralyzed limb at the initial stage after cross nerve transfer.

Reversion of transcallosal interhemispheric neuronal inhibition on motor cortex after contralateral C7 neurotization.

Department of Hand Surgery, Huashan Hospital, Fudan University, 12 Wulumuqi Middle Road, Shanghai 200040, China Department of Radiology, Huashan Hospital, Fudan University, 12 Wulumuqi Middle Road, Shanghai 200040, China PET Center, Huashan Hospital, Fudan University, 12 Wulumuqi Middle Road, Shanghai 200040, China State Key Laboratory of Medical Neuroscience, Fudan University, 138, Yi Xue Road, Shanghai 200032, China

Local and Extensive Neuroplasticity in Carpal Tunnel Syndrome: A Resting-State fMRI Study:

Carpal tunnel syndrome (CTS) is a most common peripheral nerve entrapment neuropathy characterized by sensorimotor deficits in median nerve innervated digits. Block-design task-related functional magnetic resonance imaging (fMRI) studies have been used to investigate CTS-related neuroplasticity in the primary somatosensory cortices. However, considering the persistence of digital paresthesia syndrome caused by median nerve entrapment, spontaneous neuronal activity might provide a better understanding of CTS-related neuroplasticity, which remains unexplored. The present study aimed to investigate both local and extensive spontaneous neuronal activities with resting-state fMRI. A total of 28 bilateral CTS patients and 24 normal controls were recruited, and metrics, including amplitude of low-frequency fluctuation (ALFF) and voxel-wise functional connectivity (FC), were used to explore synaptic activity at different spatial scales. Correlations with clinical measures were further investigated by linear regression. Decreased amplitudes of low-frequency fluctuation were observed in the bilateral primary sensory cortex (SI) and secondary sensory cortex (SII) in CTS patients (AlphaSim corrected P < .05). This was found to be negatively related to the sensory thresholds of corresponding median nerve innervated fingers. In the voxel-wise FC analysis, with predefined seed regions of interest in the bilateral SI and primary motor cortex, we observed decreased interhemispheric and increased intrahemispheric FC. Additionally, both interhemispheric and intrahemispheric FC were found to be significantly correlated with the mean ALFF.

Brachialis muscle transfer for reconstructing digital flexion after brachial plexus injury or forearm injury

Restoration of digital flexion after brachial plexus injury or forearm injury has been a great challenge for hand surgeons. Nerve transfer and forearm donor muscle transfer surgeries are not always feasible. The present study aimed at evaluating the effectiveness of restoring digital flexion by brachialis muscle transfer. Ten lower brachial plexus- or forearm-injured patients were enrolled. After at least 12 months following surgery, the middle-finger-to-palm distance was less than 2.5 cm in six patients. In the other four patients with less satisfactory results, secondary tenolysis surgery was performed and the middle-finger-to-palm distances were reduced to 2.0–4.0 cm. The average grasp strength was 20 ± 4 kg. Elbow flexion was not adversely affected. In conclusion, brachialis muscle transfer is an effective method for reconstructing digital flexion, not only in lower brachial plexus injury, but also in forearm injury patients. Level of evidence: IV

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

OBJECT The 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. METHODS In 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. RESULTS The 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). CONCLUSION Corpus 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.