Methods: A total of 20 consecutive live patients awaiting lumbar surgery were subjected to two magnetic resonance imaging scans on the same day in both supine and lateral decubitus positions at a single center to investigate the anterior L5/S1 disk space. Results: The bare anterior L5/S1 disk window was present in all patients of this study population, and the mean width was 27 mm in the supine and 22 mm in the lateral decubitus position, with a mean reduction of 5.2 mm between the positions. The oblique corridor angle was measured at a mean of 33°. Conclusions The bare window of L5/S1 disk space was present within this population group, and it was found to be mobile and changed significantly with patient positioning. Therefore, the spine surgeon or the access surgeon must consider the increased potential vascular risk during disk access in lateral decubitus anterior lumbar interbody spinal fusion surgery.

Methods: In this retrospective study, 43 consecutive patients who underwent SI joint fusion between August 2017 and February 2020 were enrolled; 60 SI joints were fused. The patients’ fusion was documented on computed tomography or X-rays, and Visual Analog Scale (VAS) scores were used to determine patient subjective clinical outcomes. Results: A total of 60 joints were fused, including 26 joints fused using robotic guidance and 34 joints fused using the Stealth Navigation System. Student t-test was used to compare the mean preoperative VAS score (7.52±1.3) with the mean postoperative VAS score at the 12-month follow-up (1.43±1.22) (p<0.05). The SI joint fusion rate using this technique was 61% at 6 months, 96.4% at 12 months, and 100% at 18 months. Conclusions The use of navigation guidance or robotic assistance enables accurate percutaneous screw placement across the SI joint. The use of bone morphogenetic protein in the screw bore hastens fusion across the joint, improving patient-perceived pain.