Chronic compression of the posterior longitudinal ligament of the cervical spine is associated with abnormal discharge of middle cervical ganglion.

There are abundant sympathetic nerve fibers in cervical posterior longitudinal ligament (PLL). The aim of this study was to investigate the role of PLL in the occurrence of sympathetic symptoms. Ten healthy adult beagles were selected and anesthetized to establish a PLL compression model by C4/5 discectomy, nucleus pulposus tissue replantation, and plate internal fixation. The middle cervical ganglia (MCG) activities were recorded before modeling, shortly after modeling, and two months after modeling. The waveform parameters and spectral densities of autonomic discharge of MCG among the three periods were compared. There was significant difference only in terms of the area of waveform per unit time between before and shortly after modeling. Abnormal discharge waveforms of MCG were detected in two months after modeling. The wave amplitude and waveform area per unit time in two months after modeling were increased significantly compared with those in shortly after modeling. Functional spectral decomposition found a significant increase in 100-250 Hz in two months after modeling. In conclusion, abnormal discharge of MCG caused by chronic compression of PLL may be one of the pathological basis of sympathetic nervous symptoms.