Cervical ventral epidural pressure response to graded spinal canal compromise and spinal motion

Study Design. A laboratory investigation using a feline model of graded ventral spinal canal compromise was performed. Objective. To quantify the effects of graded ventral spinal canal compromise, both in the static condition and in combination with passive spinal motion, on cervical ventral epidural pressure (CVEP). The CVEP effects of laminectomy are also investigated. Summary of Background Data. Spinal canal compromise, both in the static condition and in combination with passive spinal motion, has been implicated as a cause of spinal cord dysfunction. Methods. Seventeen cats underwent anterior corpectomy of C3 and placement of a flexible ventral graded compression device incorporating a pressure transducer. Ten animals also underwent laminectomy of C3. The implant was advanced stepwise into the spinal canal. CVEP was measured, at each degree of canal compromise, in the flexed, extended, and neutral positions, as well as during neck movement. Results. CVEP rose as a function of spinal canal compromise. In animals without laminectomy, mean CVEP was higher in the extended position and lower in the flexed position than in the neutral position. Mean CVEP during continuous passive neck movement was found to be higher than mean CVEP in the neutral position. Laminectomy was found to lower CVEP during all conditions examined, although substantial rises in CVEP were still observed in the presence of a residual ventral mass. All reported differences were statistically significant ( P < 0.05). Conclusions. CVEP is elevated by both spinal canal compromise and spinal motion.