| At present, pedicle screw fixation surgery has achieved significant popularity in spinal surgeons.However, it is difficult to control the direction and depth of the pedicle screws (PS) because of thedifferent anatomical structures of each vertebrae. The lacks of monitoring methods lead to themisplacement of PS and pedicle cortical violation, which can result in a great surgery risk.In this paper, a new method based on near-infrared spectroscopy (NIRS) and computertomography (CT) images was proposed to monitor the implantation of pedicle screw. The relationshipbetween NIRS parameters and CT values along the path of pedicle screw in vertebrae was studied,which could build the foundation for improving the accuracy of pedicle screw implantation. The mainresearch contents included:(1) By the use of three-dimensional visualization method of CT images,the best path for pedicle screw implantation and the corresponding offset paths were planned. Thecharacteristics of CT values on these paths were studied;(2) An integrated steel drill with two opticalfibers was designed, which was used in experiments of fresh pig vertebrae. Two parameters wasproved as the best NIRS monitoring factors such as the reduced scattering coefficient and thespectrum slope;(3) The correlation between CT values and NIRS monitoring factors was investigatedand the linear models were achieved to transform CT values to NIRS monitoring factors. A warningmethod to monitor the misplacement of pedicle screw were also proposed;(4) A monitoring systemsoftware for pedicle screw fixation surgery was designed and developed, which was based onVC++6.0development platform and VTK toolbox.The contributions of this paper include: a new method of pedicle screw fixation surgery base onNIRS and CT images was presented to monitor pedicle screw implantation; the linear models werebuilt to transform CT values to NIRS monitoring factors; the foundation for achieving the jointmonitoring method with CT images and NIRS were given. |
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