182. Radiation exposure in posterior lumbar fusion: a comparison of CT image-guided navigation, robotic assistance and intraoperative fluoroscopy

Abstract

BACKGROUND CONTEXT Intraoperative CT image-guided navigation (IGN) and robotic assistance have been increasingly implemented during spine surgery to improve accuracy in pedicle screw positioning. However, studies have shown that they increase operative time and ionizing radiation exposure, and it remains controversial whether they improve patient outcomes. PURPOSE Assess use of IGN and robotic assistance in posterior lumbar surgery and their relationship with patient radiation exposure and perioperative outcomes. STUDY DESIGN/SETTING Retrospective cohort study at single institution. PATIENT SAMPLE A total of 165 patients undergoing 1- or 2-level posterior spinal fusion, with or without TLIF. OUTCOME MEASURES Preoperative CT scan utilization and radiation dose, intraoperative radiation dose (fluoroscopy and/or CT) and total-procedure radiation dose (sum of preoperative CT and intraoperative radiation doses), levels fused, operative time, estimated blood loss (EBL), length of stay (LOS), postoperative complications. METHODS Patients ≥18 years old undergoing 1- or 2-level posterior spinal fusion, with or without TLIF, in a 12-month period included. Chart review performed for pre- and intraoperative data on radiation dose and perioperative outcomes. All radiation doses quantified in milli-Grays (mGy). Univariate analysis and multivariate logistic regression analysis for categorical variables and one-way ANOVA for continuous variables utilized, with significance set at p<0.05. RESULTS A total of 165 patients (51.83% F, 59.13±13.18yrs, BMI 29.43±6.72, Charlson comorbidity index [CCI] 1.20±1.56) were assessed: 12 IGN, 62 robotic, 56 open, 35 MIS without IGN/robotics. Lower proportion of women in open and MIS group (66.67% F IGN, 64.52% robotic, 38.18% open, 45.71% MIS, p=0.010). Younger patients in MIS group (63.42 yrs IGN, 61.74 robotic, 60.63 open, 50.63 MIS, p<0.001). MIS group had lowest mean posterior levels fused (1.42 IGN, 1.27 robotic, 1.32 open, 1.06 MIS, p=0.015). Total-procedure radiation (50.21mGy IGN, 59.84 robotic, 22.56 open, 82.02 MIS), total-procedure radiation/level fused (41.88mGy IGN, 51.18 robotic, 18.56 open, 79.41 MIS) and intraop radiation (44.69mGy IGN, 44.85 robotic, 14.81 open, 80.28 MIS) were lowest in the open group and highest in the MIS group compared to IGN and robotic (all p<0.001). A higher proportion of robotic and lower proportion MIS patients had preop CT (25% IGN, 82.26% robotic, 37.5% open, 8.57% MIS, p<0.001). EBL (441.67mL IGN, 380.24 robotic, 355.36 open, 162.14 MIS, p=0.002) and LOS (4.75 days IGN, 3.89 robotic, 3.89 open, 2.83 MIS, p=0.039) were lowest in the MIS group. Highest operative time for IGN patients (303.5 min vs 264.85 robotic, 229.91 open, 213.43 MIS p<0.001). No differences in BMI, CCI, postoperative complications (p=0.313, 0.051, 0.644, respectively). CONCLUSIONS IGN and robotic assistance in posterior lumbar fusion were associated with higher intraoperative and total-procedure radiation exposure than open cases without IGN/robotics, but significantly less than MIS without IGN/robotics, without differences in perioperative outcomes. While MIS procedures reported highest radiation exposure to patient, of more concern is that the proportion of total radiation dose applied to surgeon would also be considerably higher in MIS group. FDA DEVICE/DRUG STATUS Brainlab Airo Mobile Intraoperative CT scanner (Approved for this indication). Intraoperative CT image-guided navigation (IGN) and robotic assistance have been increasingly implemented during spine surgery to improve accuracy in pedicle screw positioning. However, studies have shown that they increase operative time and ionizing radiation exposure, and it remains controversial whether they improve patient outcomes. Assess use of IGN and robotic assistance in posterior lumbar surgery and their relationship with patient radiation exposure and perioperative outcomes. Retrospective cohort study at single institution. A total of 165 patients undergoing 1- or 2-level posterior spinal fusion, with or without TLIF. Preoperative CT scan utilization and radiation dose, intraoperative radiation dose (fluoroscopy and/or CT) and total-procedure radiation dose (sum of preoperative CT and intraoperative radiation doses), levels fused, operative time, estimated blood loss (EBL), length of stay (LOS), postoperative complications. Patients ≥18 years old undergoing 1- or 2-level posterior spinal fusion, with or without TLIF, in a 12-month period included. Chart review performed for pre- and intraoperative data on radiation dose and perioperative outcomes. All radiation doses quantified in milli-Grays (mGy). Univariate analysis and multivariate logistic regression analysis for categorical variables and one-way ANOVA for continuous variables utilized, with significance set at p<0.05. A total of 165 patients (51.83% F, 59.13±13.18yrs, BMI 29.43±6.72, Charlson comorbidity index [CCI] 1.20±1.56) were assessed: 12 IGN, 62 robotic, 56 open, 35 MIS without IGN/robotics. Lower proportion of women in open and MIS group (66.67% F IGN, 64.52% robotic, 38.18% open, 45.71% MIS, p=0.010). Younger patients in MIS group (63.42 yrs IGN, 61.74 robotic, 60.63 open, 50.63 MIS, p<0.001). MIS group had lowest mean posterior levels fused (1.42 IGN, 1.27 robotic, 1.32 open, 1.06 MIS, p=0.015). Total-procedure radiation (50.21mGy IGN, 59.84 robotic, 22.56 open, 82.02 MIS), total-procedure radiation/level fused (41.88mGy IGN, 51.18 robotic, 18.56 open, 79.41 MIS) and intraop radiation (44.69mGy IGN, 44.85 robotic, 14.81 open, 80.28 MIS) were lowest in the open group and highest in the MIS group compared to IGN and robotic (all p<0.001). A higher proportion of robotic and lower proportion MIS patients had preop CT (25% IGN, 82.26% robotic, 37.5% open, 8.57% MIS, p<0.001). EBL (441.67mL IGN, 380.24 robotic, 355.36 open, 162.14 MIS, p=0.002) and LOS (4.75 days IGN, 3.89 robotic, 3.89 open, 2.83 MIS, p=0.039) were lowest in the MIS group. Highest operative time for IGN patients (303.5 min vs 264.85 robotic, 229.91 open, 213.43 MIS p<0.001). No differences in BMI, CCI, postoperative complications (p=0.313, 0.051, 0.644, respectively). IGN and robotic assistance in posterior lumbar fusion were associated with higher intraoperative and total-procedure radiation exposure than open cases without IGN/robotics, but significantly less than MIS without IGN/robotics, without differences in perioperative outcomes. While MIS procedures reported highest radiation exposure to patient, of more concern is that the proportion of total radiation dose applied to surgeon would also be considerably higher in MIS group.