Comparative Study of C-Arms for Intraoperative 3-dimensional Imaging and Navigation in Minimally Invasive Spine Surgery Part II

Abstract

Study Design: A radiation exposure study in vitro. Objective: This study aimed to compare the radiation exposure of 2 different 3-dimensional (3D) C-arm devices on an anthropomorphic phantom. Summary of Background Data: Minimally invasive pedicle screw placement requires intraoperative imaging techniques for visualization of the unexposed spine. Mobile 3D C-arms compose a 3D image data set out of multiple successive fluoroscopic images. Methods: We compared the 3D C-arm devices Siremobil Iso-C 3D (Siemens Sector Healthcare, Erlangen, Germany) and Vision FD Vario 3D (Ziehm Imaging, Nuremberg, Germany) regarding their radiation exposure. For this purpose, dosimeters were attached on an anthropomorphic phantom at various sites (eye lenses, thyroid gland, female, and male gonads). With each C-arm, 10 automated 3D scans as well as 400 fluoroscopic images were performed on the cervical and lumbar spine, respectively. Results: The Vision FD Vario 3D generally causes higher radiation exposures than the Siremobil Iso-C 3D. Significantly higher radiation exposures were assessed at the eye lenses performing cervical (294.1 vs. 84.6 μSv) and lumbar 3D scans (22.5 vs. 11.2 μSv) as well as at the thyroid gland performing cervical 3D scans (4405.2 vs. 2761.9 μSv). Moreover, the Vision FD Vario 3D caused significantly higher radiation exposure at the eye lenses for standard cervical fluoroscopic images (3.2 vs. 0.4 μSv). Conclusions: 3D C-arms facilitate minimally invasive and accurate pedicle screw placement by providing 3D image datasets for intraoperative 3D imaging and navigation. However, the hereby potentially increased radiation exposure has to be considered. In particular, the Vision FD Vario 3D appears to generally evoke higher radiation exposures than the Siremobil Iso-C 3D. Well-indicated application of ionizing radiation and compliance with radiation protection principles remain mandatory to keep radiation exposure to patient and staff as low as reasonably achievable.