Patient-specfic 3D virtual planning using virtual fluoroscopic images to improve sacroiliac joint fusion: a retrospective cohort study

In 15-25% of the patients with low back pain the pain is caused by sacroiliac (SI) joint dysfunction. It can be treated with sacroiliac joint fusion (SIJF), i.e. a treatment that involves stabilisation of the joint with triangular titanium implants. This treatment is commonly performed using 2D fluoroscopic guidance, but certain factors make it challenging to place the implants without damaging surrounding neural structures. A possible method to overcome these factors can be virtual surgical planning (VSP).
A method for VSP in SIJF was developed and implemented in clinical practice. The implants are virtually inserted inside a CT scan. 3D models are used to create virtual fluoroscopic images. These mimic the intraoperative images and allow the surgeon to place the implants according to the VSP. Based on postoperative CT imaging, implant placement accuracy was evaluated. Furthermore, malpositioning complications, a learning curve, and the added value based on the surgeon's perspective were evaluated.
Twenty-eight interventions were performed. The overall mean implant placement accuracy had a deviation of 5.0 mm between the apexes, and the angle between the planned and placed implant was 4.4°. The surgeon was exceptionally positive about VSP for SIJF.
The implants were placed with relatively high accuracy. No major malpositioning complications occurred. VSP was a valuable addition to SIJF. Without a measurable learning curve, we expect that other surgeons can relatively easily adopt VSP for SIJF. In future research, it is recommended to perform a study that compares VSP for SIJF to the conventional procedure.