The Influence of Coughing on Cerebrospinal Fluid Pressure in an In Vitro Syringomyelia Model With Spinal Canal Stenosis

Five in vitro models were constructed which were representative of various pathologies of the spinal canal (SC) associated with syringomyelia (SM). The models were subjected to a cough type flow impulse while monitoring the pressure environment in the syrinx and subarachnoid space (SAS) regions of the model. The results indicated that conditions can arise during a cough which would provide pressure forces to encourage cerebrospinal fluid (CSF) movement into the syrinx cavity. The flow obstruction (stenosis) acted as an inflection point for transmural pressure (TP) in which the far region of the syrinx was expanded and the near region was compressed. In the case when a stenosis was present, but no syrinx had formed, the longitudinal pressure gradient and pulse pressures were highest on the SC. However, when a syrinx was present, the pressures were reduced, but still pathological. The primary point of pressure gradients in all of the experiments was the stenosis which caused large pressure dissociation in the system which could aid in SC ripping or tearing of the tissue. The presence of a syrinx appeared to decrease some of these forces, but without removal of the flow obstruction, a pathological biomechanical environment persists.