| 摘要 |
A manually operated pedicle locator instrument measures the static permittivity of matter to locate pedicles in vertebral or bony structures. The locator senses and compares the dielectric constants of the pedicle and the surrounding matter. When the operative component of the locator, the component which contains controlled capacitors, is placed over non-pedicle material, the locator will sense one dielectric constant. However, when it is placed over a pedicle, there is a different dielectric constant. The locator operates on this capacitance difference generated by differences in density. Circuitry in the locator senses this change and sends the change signal to indicator lights located on the locator. A switch on the locator allows the surgeon to select different levels of capacitance in order to identify thicknesses of different bony structures, i.e. structures in cervical, thoracic, and lumbar vertebral bodies.
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