Direct spinal cord injury during cervical epidural and nerve root blocks: A case series and pathophysiological reevaluation.

Cervical epidural and nerve root blocks effectively manage radicular pain but pose risks of severe neurologic complications, including acute myelopathy. Although vascular embolization of particulate steroids is often implicated in these events, direct mechanical spinal cord injury remains an underrecognized etiology. Identifying the true pathophysiologic mechanism is essential to prevent permanent neurological deficits. We retrospectively reviewed four patients who developed acute spinal cord injuries immediately following cervical nerve blocks or targeted acupuncture. We analyzed clinical presentations, intraprocedural events, and longitudinal magnetic resonance imaging (MRI) findings to elucidate the underlying mechanism of injury. All patients reported an instantaneous, excruciating "electric shock-like" sensation during needle insertion, followed immediately by severe motor weakness and paresthesia. MRI consistently revealed focal, central T2-weighted high signal intensities strictly localized within the spinal cord parenchyma. Unlike typical vascular infarctions following specific arterial territories, these findings strongly correlate with the physical trajectory of a direct needle puncture. The pathognomonic intraprocedural electric shock sensation and the central localization of MRI lesions strongly suggest direct mechanical needle injury as a primary cause of these catastrophic complications. Immediate cessation of needle advancement upon patient report of a shock-like sensation is critical to prevent irreversible spinal cord damage.