Anatomische und biomechanische Untersuchungen zur Optimierung und Risikominimierung der segmentalen spinalen Wirbelsäuleninstrumentation bei neuromuskulärer Skoliose
Operative stabilisation of a scoliotic spine is performed following two different concepts: sublaminar segmental spinal instrumentation (SSSI) and interspinous segmental spinal instrumentation (ISSI). According to recent clinical and experimental studies ISSI is believed to achieve almost the stability of SSSI without having the neurological risk of SSSI. The aim of this experimental study was to compare biomechanically interspinous instrumented cadaver spines with sublaminar instrumented cadaver spines with respect to their stability under constantly increasing pullout forces (static force). Additionally, using a geometrical model, the theoretical risk for wire penetration of the neural canal (ISSI technique) was evaluated. The first main chapter of this dissertation describes the disease "scoliosis" in detail. In the second main chapter the data of ten instrumented cadaver spine was analysed. In total 50 tests were performed: single and double sublaminar wires, button-wires and button-wires with crimps. In all measurements the stability of the bone was the limiting factor for stability of the implant, there was no failure of the wires. The interspinous instrumentation (ISSI) achieved significantly lower pull-out forces (30-45%) than the sublaminar instrumentation (SSSI). The anatomical measurements of the vertebras of nine macerated spines revealed a 11%-50% risk for penetration of the neural canal depending on the level of wire insertion. In all spine levels female vertebras showed a higher risk for penetration. In contrast to other biomechanical studies interspinous segmental spinal instrumentation (ISSI) seems to withstand significantly lower pull-out forces than segmental sublaminar spinal instrumentation (SSSI). The risk for neurological damage by penetration of the neural canal is also present in ISSI and depends on the position of the wire in the vertebra.
info:eu-repo/classification/ddc/610, Medizin
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