Impact of surgery on the outcome after spinal cord injury – current concepts and an outlook into the future

Traumatic spinal cord injury（SCI）remains a devastating neurological disorder leading to severe consequences for the affected individual and their families.Further,socioeconomic implications should not be neglected as well.Although life expectancy after SCI increased tremendously,therapeutic treatment options remain limited.

Surgical reconstruction of spinal cord circuit provides functional return in humans

This mini review describes the current surgical strategy for restoring function after traumatic spinal nerve root avulsion in brachial or lumbosacral plexus injury in man. As this lesion is a spinal cord or central nervous injury functional return depends on spinal cord nerve cell growth within the central nervous system. Basic science, clinical research and human application has demonstrated good and useful motor function after ventral root avulsion followed by spinal cord reimplantation. Recently, sensory return could be demonstrated following spinal cord surgery bypassing the injured primary sensory neuron. Experimental data showed that most of the recovery depended on new growth reinnervating peripheral receptors. Restored sensory function and the return of spinal reflex was demonstrated by electrophysiology and functional magnetic resonance imaging of human cortex. This spinal cord surgery is a unique treatment of central nervous system injury resulting in useful functional return. Further improvements will not depend on surgical improvements. Adjuvant therapy aiming at ameliorating the activity in retinoic acid elements in dorsal root ganglion neurons could be a new therapeutic avenue in restoring spinal cord circuits after nerve root avulsion injury.

A Surgery Protocol for Adult Zebrafish Spinal Cord Injury

Adult zebrafish has a remarkable capability to recover from spinal cord injury,providing an excellent model for studying neuro-regeneration. Here we list equipment and reagents,and give a detailed protocol for complete transection of the adult zebrafish spinal cord. In this protocol,potential problems and their solutions are described so that the zebrafish spinal cord injury model can be more easily and reproducibly performed.In addition,two assessments are introduced to monitor the success of the surgery and functional recovery：one test to assess free swimming capability and the other test to assess extent of neuroregeneration by in vivo anterograde axonal tracing.In the swimming behavior test,successful complete spinal cord transection is monitored by the inability of zebrafish to swim freely for 1 week after spinal cord injury,followed by the gradual reacquisition of full locomotor ability within 6 weeks after injury.As a morphometric correlate,anterograde axonal tracing allows the investigator to monitor the ability of regenerated axons to cross the lesion site and increasingly extend into the gray and white matter with time after injury,confirming functional recovery.This zebrafish model provides a paradigm for recovery from spinal cord injury,enabling the identification of pathways and components of neuroregeneration.