dc.description.abstract | Pedicle screw implantation is a high-risk operation. In the conventional operation, the surgeon must take many C-arm images to confirm that the surgical instruments will not injure the spinal cord by mistake, which will cause patients and medical staff to expose high radiation risk. In addition, the operation is highly relying on the surgeon’s skill and clinic experiences. Therefore, it is needed to develop a robotic navigation system that can assist surgeons to position and hold surgical tools for spine surgery.
This research refers the existing robotic positioning and 3D C-arm navigation technology in the laboratory to develop a 3D C-arm image assisted robotic navigation system. The main studies include the software integration of robotic system and navigation system with segmentation method improvement of steel marker images, design of assistive navigation devices, patient and image coordinate registration, design of path planning window with translation and rotation buttons, and experiments of robotic positioning accuracy. Further, an automatic image threshold setting for separating steel markers from the C-arm image is developed, which should be applicable for different 3D C-arm and X-ray intensity setting. Also, connecting area analysis and characteristics of sphere are used to identify features of steel sphere models so that intuitive facilitate adjustment can be done when different C-arm equipment is used.
The average positioning distance and direction error of the system were tested by using the verification board (V) and the verification device (SV). The coordinates of physical features of the testing devices are defined as control group(C);the transferred coordinates of image features of the testing devices are defined as group(T);the position and direction of the positioning probe navigated by the robot to the planned path are defined as group(T^′′). After at least three-time testing, the registration error(|C-T|) and system positioning error (|C-T^′′ |) are |C-T|=0.86±0.10mm, |C-T^′′ |=1.27±0.47mm based on V board;|C-T|:0.89±0.40mm (end point), 0.72±0.29mm (entry point), 0.43±0.13° (direction);|C-T^′′ |:1.67±0.36mm (end point), 1.51±0.28mm (entry point), 0.54±0.24° (direction) based on SV device. The overall position errors are lower than 2mm, a requirement for pedicle screw implantation.
Keyword:C-arm Image, Surgical Navigation, Robot, Spine Surgery
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