Anterior Extrusion of an Orthobiologic Sacroiliac Joint Implant in a Patient With Psoriatic Arthritis

ABSTRACT Background Sacroiliac joint (SIJ) pain accounts for a large portion of low back pain within the population. Management for this SIJ pain consists of many non‐invasive treatments including physical therapy, nerve ablation, intra‐articular SIJ injections, bracing, and manipulative therapy. Pain that proves to be resistant to these modalities has previously been considered for surgical stabilization through a transiliac approach, which involves placement of screws. Aims To describe the anterior extrusion of a SIJ implant following arthrodesis, which is a unique complication of a minimally invasive SIJ fusion via the posterior approach. Materials and Methods A 52 year old female with a past medical history of psoriatic arthritis and alanto‐axial instability presented with a year‐long history of bilateral lower back and right‐sided posterior thigh and buttock pain. Evaluation included lumbar MRI and pelvic CT. Based on these findings, she underwent minimally invasive posterior SIJ fusion using the LinQ allograft. Her symptoms and response to treatment were documented throughout her clinic follow‐ups. Results Imaging revealed degenerative SIJ changes. She subsequently underwent several rounds of SIJ steroid injections. Due to continued pain, she opted to have a minimally invasive SIJ fusion via the posterior approach, first on the right side and then on the left side. After several months of persistent, reaggravated SIJ pain, a repeat pelvic CT showed anterior extrusion of the right SIJ allograft. Discussion More recently, multiple minimally invasive techniques for SIJ fusions have been developed, one of them being posterior insertion of an orthobiologic implant. Minimally invasive SIJ fusion has been shown to provide pain relief and decrease disability. Posterior implant insertion to partially fuse the SIJ carries minimal risk of complications, one of which is posterior dislodgment of the implant. However, anterior extrusion of the implant has not, to our knowledge, been described or reported.