Spinal cord extracellular microenvironment. Can the changes resulting from trauma be graded?

It is now clear that alternatives are available to the standard method of producing spinal injury with the Allen drop technique. We have shown that small groups of animals with predictably consistent mechanical injury descriptors can now be produced for studies of this type. These groups can easily be selected to have minimal or maximal injury results, depending upon this series of mechanical descriptors. In addition, important physiological variables seem to show acute recovery patterns consistent with recovery of function in chronic animals. Since marginal injuries are likely to be more responsive to pharmacological or surgical intervention, a sensible approach would be to design studies in which animals are close to, but not at, some degree of injury from which they will spontaneously recover. Shifts of the acute physiological, chronic behavioral, or histopathological recovery curves would then indicate the potential therapeutic index of different interventions. Only in this way can significant advances be made in the selection of protocols for human trials.