Objective: Robot-assisted pedicle screw placement in spinal fusion has been well studied. However, few studies have evaluated robot-assisted sacroiliac joint (SIJ) fusion. The aim of this study was to compare surgical characteristics, accuracy, and complications between robot-assisted and fluoroscopically guided SIJ fusion.
Methods: A retrospective review of 110 patients with 121 SIJ fusions done at a single academic institution was conducted from 2014 to 2023. Inclusion criteria included adult age and a robot- or fluoroscopically guided approach to SIJ fusion. Patients were excluded if the SIJ fusion was part of a longer fusion construct, not minimally invasive, and/or had missing data. Demographics, approach type (robotic vs fluoroscopic), operative time, estimated blood loss (EBL), number of screws, intraoperative complications, 30-day complications, number of intraoperative fluoroscopic images (as a surrogate for radiation exposure), implant placement accuracy, and pain status at the first follow-up were recorded. Primary endpoints were SIJ screw placement accuracy and complications. Secondary endpoints were operative time, radiation exposure, and pain status at the first follow-up.
Results: Ninety patients were included who underwent a total of 101 SIJ fusions, of which 78 were robotic and 23 were fluoroscopic. The mean age of the cohort at the time of surgery was 55.9 ± 13.8 years; 46 patients were females (51.1%). No difference was found in screw placement accuracy between robotic and fluoroscopic fusion (1.3% vs 8.7%, p = 0.06). Chi-square analysis of robotic versus fluoroscopic fusion found no difference in the presence of 30-day complications (p = 0.62). Mann-Whitney U-test analysis found that robotic fusion had a significantly longer operative time than fluoroscopic fusion (72.0 vs 61.0 minutes, p = 0.01); however, robot-assisted fusions involved significantly lower radiation exposure (26.7 vs 187.4 fluoroscopic images, p < 0.001). No difference in EBL was noted (p = 0.17). No intraoperative complications were present in this cohort. Subgroup analysis comparing the 23 most recent robotic cases against the 23 fluoroscopic cases found that robotic fusion still was associated with significantly longer operative times than fluoroscopic fusion (74.0 ± 26.4 vs 61.0 ± 14.9 minutes, respectively; p = 0.047).
Conclusions: SIJ screw placement accuracy did not significantly differ between robot-assisted and fluoroscopic SIJ fusion. Complications overall were low and similar between the two groups. The operative time was longer with robotic assistance, but there was markedly less radiation exposure to the surgeon and staff.
Keywords: complications; fluoroscopic fusion; minimally invasive surgery; pedicle screw; robot-assisted surgery; sacroiliac joint fusion; spinal fusion.