| Explanation for the formation of cystic cavities within the spinal cord (SC) is not fully realized. The presence of a cyst (syrinx) in the spinal cord, termed syringomyelia (SM), can produce a wide variety of symptoms ranging from mild discomfort to paralysis depending on syrinx location and severity. SM and the related disorder Chiari malformation, has been shown to occur in ∼1/27,000 people in the US. Many theories have been developed towards an explanation for the pathogenesis of SM, however experimental evidence is needed to better explain the mechanisms of syrinx formation. The goal of this thesis work is to provide experimental evidence for the testing of existing SM theories and contribute toward the development of an amalgamated SM theory.;Experiments were conducted on nine in vitro models representative of various supposed underlying pathological mechanisms responsible for SM including: SC mechanical properties, various types of spinal stenosis, influence of coughing, cerebrospinal fluid (CSF) waveform frequency, CSF pulse amplitude, SC tensioning, and shunting procedures. Results indicated that wave transmission speed was found to be a function of the spinal conduit compliance and not the SC properties. The SAS stenosis and syrinx were shown to act together with a valve-like mechanism which could encourage CSF movement into the SC. Venturi effect distending the SC outward, at the point of stenosis, was not identified when a syrinx was present. Relaxation of SC tension, in a model representative of post traumatic syringomyelia (PTS), resulted in forces which could encourage syrinx growth. Coughing conditions produced an inflection of the transmural pressure differentials across the SAS stenosis which could damage SC tissue and move fluid into the cyst. High CSF flow frequency and magnitude resulted in pressures which would encourage fluid movement into the syrinx over the entire CSF flow cycle. Shunting the SAS CSF flow reduced forces which cause syrinx distension, but did not entirely change the hydrodynamic environment. In conclusion, the provided detailed experimental analysis of the complex interactions present in SM help to explain syrinx progression. |
