Chong Hing Wong1*#, Yoshihisa Kotani2*#, Junichi Tochio3, Hiromitsu Takeda4, Masamoto Takano3 and Norimasa Iwasaki5
1Department of Orthopedics and Traumatology, Princess Margaret Hospital, China
2Department of Orthopedic Surgery and Spine and Spinal Cord Center, Steel Memorial Muroran Hospital, Japan
3Department of Radiology, Steel Memorial Muroran Hospital, Japan
4Department of Radiology, Sapporo Medical University Hospital, Japan
5Department of Orthopedic Surgery, Hokkaido University Graduate School of Medicine, Japan # Both authors contributed equally
Objective: To evaluate the radiation exposures (RE) to patient and surgeon during minimally invasive lumbar spine surgery with instrumentation under the use of C-arm image intensifier or O-arm intraoperative CT.
Background: Minimally invasive spinal instrumentation is highly dependent on intraoperative imaging because of limited exposure of anatomic landmarks. The choice of imaging tools is important not only for accuracy but also safety. Recently introduced O-arm with navigation is a promising tool that could help to solve many problems encountered with C-arm, but the possible increase in RE is a concern.Materials and
Methods: Twenty-five patients were included in this study; 11 patients who received C-arm assisted surgery (8 PLF, 3 TLIF) and 14 patients who received O-arm assisted lumbar fusion surgery (9 PLF, 5 TLIF). Patients were further divided into three subgroups: TLIF using bilateral mini-Wiltse approach, midline approach TLIF, and midline approach PLF. Surgeon RE was evaluated using a personal finger dosimeter. Patient's exposure was evaluated by an internal dose registration systems of C-arm or O-arm devices respectively and converted into effective dose (ED) using the established tissue weighting factors (WF). The O-arm (CT mode) ED was calculated as Dose Length Product (DLP) x conversion index. The DLP=Computed Tomography Dose Index weighted (CTDIw) x irradiated area (cm2). C-arm ED was calculated as Skin Surface Dose (SSD) (mGy) × WF sum.Results: The overall mean surgeon RE was 2.19 mSv in C-arm group and 0 mSv in O-arm group (p=0.0003) and the overall mean patient ED was 41.85 mSv in C-arm group and 16.09 in O-arm group (p=0.0004). The value was also lower in each O-arm subgroups when compared to corresponding C-arm subgroups.Conclusion: We introduced O-arm at our facility to allow the use of precise navigation during surgery. Despite 2 or more CT acquisitions per surgery, the surgeon's RE was completely avoided and patient's RE was reduced to less than a half that of C-arm's, which proves that O-arm is beneficial for both surgeon and patients in MIS lumbar fusion surgery.
Radiation exposure; C-arm; O-arm; Minimally invasive spinal instrumentation
Wong CH, Kotani Y, Tochio J, Takeda H, Takano M, Iwasaki N. Comparison of Intraoperative Radiation Exposure for O-Arm Intraoperativect vs. C-Arm Image Intensifier in Minimally Invasive Lumbar Fusion. Clin Surg. 2017; 2: 1558.