A novel mouse model simulating <scp>C5</scp> palsy after cervical surgery

BACKGROUND: The incidence of C5 palsy after cervical surgery (C5P) was high (>5%), although its pathogenesis is still not clear. Although most patients (>95%) could have apparent enhancement, there are still some patients who cannot achieve satisfactory functional recovery, and it seriously affects their quality of life. At present, there is no appropriate animal model that could be used to research new interventions for permanent C5P. METHODS: Following anatomical validation confirming precise exposure of the C5 ventral root, we established a novel mouse C5P model using a posterior intradural approach to selectively transect the C5 ventral root while preserving the dorsal root and avoiding lateral/anterior cervical dissection. Multimodal validation (behavioral, electrophysiological, histological) confirmed selective motor deficits, denervation atrophy, and intact sensory pathways. RESULTS: The posterior approach for intradural C5 ventral nerve root injury offers sufficient operative space and is a safe surgical technique, ensuring the successful postoperative survival of all mice involved. By excising the C4 and C5 vertebral arches to facet joint and opening the spinal dura mater and arachnoid mater, the ventral root of C5 can be clearly exposed and severed, whereas the dorsal root can be well preserved. Behavioral and electrophysiological tests showed functional lesion, and histological assessments revealed pathological changes in muscle and nerve tissues. CONCLUSIONS: This study describes a simple, reproducible, and effective mouse model of permanent C5P for exploring potential new therapies (such as nerve transfer surgery and other cutting-edge rehabilitations).