RESUMEN
Traumatic brain injury (TBI) is a significant cause of human disability, and understanding its spontaneous recovery pattern after injury is critical for potential treatments. However, studies on the function of the contralesional cortex after TBI have mostly focused on acute-phase changes, and long-term dynamic changes in the control of the affected limb by the contralesional cortex are less understood. To unravel long-term adaptations in the contralesional cortex, we developed a mouse model of TBI and used longitudinal optogenetic motor mapping to observe the function of contralesional corticospinal neurons (CSNs) projecting to the unilateral seventh cervical (C7) segment of the spinal cord. We injected a retrograde adeno-associated virus (AAV) expressing channelrhodopsin-2 to optogenetically stimulate and map the functional connections of the motor-sensory cortex. We validated the effectiveness of transcranial optogenetic stimulation for functional mapping and observed a general increase in the control of the affected limb by the contralesional cortex over time. Using retrograde labeling techniques, we showed that TBI does not affect the distribution of C7-CSNs but alters their function, and the labeled CSNs are concentrated in the caudal and rostral forelimb areas. Our findings provide new insights into harnessing contralesional cortical plasticity to improve treatment for affected limbs. This study sheds light on the long-term adaptations in the contralesional cortex after TBI, paving the way for potential clinical applications of optogenetic stimulation to improve motor control and rehabilitation outcomes.
RESUMEN
BACKGROUND: Contralateral C7 to C7 cross nerve transfer has been proved to be safe and effective for patients with spastic arm paralysis due to stroke and traumatic brain injury. For the lower limb, contralateral L5 to S1 cross nerve transfer serves as a novel surgical approach. In many cases, patients with hemiplegia have both upper and lower limb dysfunction and hope to restore all limb functions within one operation. To cope with this demand, we performed combined contralateral C7 to C7 and L5 to S1 cross nerve transfer in two cases successfully. CASE DESCRIPTION: Two patients were enrolled in this study. The first patient is a 36-year-old woman who had spasticity and hemiplegia in both upper and lower limbs on the left side after a right cerebral hemorrhage 14 years prior. The second patient is a 64-year-old man who suffered from permanent muscle weakness in his right limbs, especially the leg, after a left cerebral hemorrhage 7 years prior. Both patients underwent the combined nerve transfer to improve upper and lower limb motor functions simultaneously. During the 10-month follow-up after surgery, the limb functions of both patients improved significantly. CONCLUSIONS: This study demonstrates the safety and benefits of combined contralateral C7 to C7 and L5 to S1 cross nerve transfer for hemiplegic patients after stroke. This novel combined surgical approach could provide an optimal choice for patients suffering from both upper and lower limb dysfunction, to reduce hospital stay while reducing financial burden.
RESUMEN
INTRODUCTION: Ultrasound has been commonly employed for depicting the morphology of the lesions in patients with radial nerve neuropathy, including entrapment, tumor, trauma, and iatrogenic injury. However, few studies have evaluated the efficacy of ultrasound for visualizing radial nerve lesions with coexistent plate fixation of humeral shaft fractures. This study aimed to address this special clinical issue. METHODS: We retrospectively examined the efficacy of ultrasound for visualizing radial nerve lesions with coexistent plate fixation of humeral shaft fractures based on intraoperative findings in patients who were treated in our hospital from January 2007 to June 2019. RESULTS: Forty-six patients were included, and there was a 100% concordance between the ultrasound and intraoperative findings on radial nerve lesions. Ultrasonography revealed four types of lesions: radial nerve in continuity in thirty-one patients, neuroma in continuity in four patients, radial nerve stuck under the plate in three patients, and radial nerve transection in eight patients. The lesion radial nerve in continuity comprised two situations according to intraoperative electrodiagnostic test results, which could not be differentiated by ultrasonography, radial nerve in continuity treated with neurolysis in twenty-five patients and radial nerve in continuity treated with nerve graft in six patients. CONCLUSION: Ultrasonography can accurately depict radial nerve lesions with coexistent plate fixation of humeral shaft fractures. It provides a basis for determining the extent of nerve damage in all patients except those with the lesion radial nerve in continuity, which is conducive to making treatment decisions as early as possible.
