Abstract
Introduction
Intraoperative imaging is critical in spine surgery for determining the spinal level, visualizing alignment, and guiding implant placement. Imaging modalities include plain X-rays, fluoroscopy with C-arm and intraoperative CT scanning (O-arm). These imaging modalities emit ionizing radiation to the surgical team and the patient. The amount of radiation emitted to the patient and the surgeon with intraoperative CT-based spine navigation were compared. The impact of intraoperative CT on the use of intraoperative X-rays and postoperative X-rays and CTs was investigated.
Material and Methods
An ambispective review of surgical cases using intraoperative CT at Vancouver General Hospital over 1 year was performed. The number of intraoperative X-rays, fluoro and CT dosages were recorded and standardized to effective doses. The number of perioperative imaging investigations was compared with a cohort of surgical cases involving only intraoperative X-rays and fluoroscopy. A literature review was performed to enable a comparison of radiation exposure to historical values for fluoroscopic-guided spine instrumentation.
Results
A total of 73 surgical cases involving an average of 5.44 levels of instrumentation were reviewed. Thoracic and lumbar spine instrumentations were associated with the highest radiation emission from all modalities compared with cervical and cases (TL: 5.65 mSv vs. C: 2.19 mSv). Major deformity and degenerative cases involved more radiation exposure than trauma and oncology cases (5.81 vs. 3.54 mSv). On average, the patient was exposed to 5.9 times more radiation compared with the surgical team. Patient exposure was three times the values reported in the literature for open thoracolumbar fusions. In comparison, radiation exposure to the surgeon was reduced by 35% compared with conventional fluoroscopically guided open thoracolumbar fusions and 70% less than minimally invasive thoracolumbar fusions. The average radiation total radiation exposure to the patient was 6.05 mSv, a value less than a single lumbar CT scan (7.5–10 mSv). The use of intraoperative CT did not reduce the number of postoperative X-rays or CT scans acquired during the admission or within 1 year following surgery.
Conclusion
Intraoperative CT increases the radiation exposure to the patient and reduces the radiation exposure to the surgeon when compared with the fluoroscopic-guidance radiation exposure reported in the literature. Thoracolumbar instrumentations for major deformity and degenerative diagnoses are associated with the highest radiation exposure. Although intraoperative CT can improve the accuracy of spine instrumentation, surgeons should be aware of the increased radiation exposure to the patient compared with conventional fluoroscopy-guidance.