The concept of vertebral instability has evolved in the last years, given the last scientific evidences on the degenerative cascade. Another concept has been developed in a parallel way to the one of the vertebral instability: it is the concept of microinstability, intended as biomechanical dysfunction of the motor spinal unit, responsible of symptoms but not showed by dynamic X-Rays. The introduction of the concept of microinstability has increased the diagnostic capacities towards low back

more »

... n and, subsequently, the therapeutic choices, but has increased the number of medico-legal issues related to the diagnostic and therapeutic pathway of this condition. Many issues related to microinstability have to be explained, to guarantee to the patients the best treatment available and, at the same time, to uphold the surgeon to perform the treatment in a safe condition. Our group has proposed a test, developed with the aim to furnish quantitative data on the basis of radiological examinations that can diagnose microinstability, giving indications on diagnosis and therapy of the dysfunctional phase of the degenerative cascade. The retrospective analysis seems to validate the test, with a good predictive value, mainly towards Adjacent Segment Syndrome (ASD). The few cases analysed in a perspective manner, even if in preliminary phase and with a short follow-up, seem to confirm the data. Only in a few cases those examinations need a diagnostic integration with a CT scan, providing further information about the degeneration of the facet joints and their grade of tropism. The only examination that can provide a diagnosis of instability J o u rn al of S p in e