SI Joint Stabilization in Long Fusion to the Pelvis

Open to people ages 21-75

1. Age 21-75 at time of screening
2. Patient scheduled for multilevel (>3 levels) spinal fusion surgery with planned fixation to the pelvis using S2AI screws
3. Patient has signed study-specific informed consent form
4. Patient has the necessary mental capacity to participate and is physically able to comply with study protocol requirements

1. Indication for multilevel spine fusion surgery is any of the following:
   1. Congenital neuromuscular disease
   2. Prior pelvic fixation (i.e., patient already has S2AI or iliac bolts in place, current surgery indicated to revise this hardware)
   3. Grade IV spondylolisthesis
2. Prior sacroiliac joint fusion/fixation on either side
3. Presence of spinal cord stimulator
4. Presence of severe hip pain that could impair functional and quality of life improvement from complex spine surgery
5. Surgeon plans to use iliac screw for pelvic fixation
6. Any known sacral or iliac pathology
7. Any condition or anatomy that makes treatment with the iFuse Implant System infeasible
8. Known metabolic bone disease

9. Severe osteoporosis

   10. Known allergy to titanium or titanium alloys 11. Use of medications known to have detrimental effects on bone quality and soft-tissue

   healing

   12. Neurologic condition that would interfere with postoperative physical therapy 13. Current local or systemic infection that raises the risk of surgery 14. Patient currently receiving or seeking short- or long-term worker's compensation

   and/or currently involved in injury litigation related to the SI joint or low back pain.

   15. Currently pregnant or planning pregnancy in the next 2 years 16. Prisoner or a ward of the state. 17. Known or suspected drug or alcohol abuse 18. Uncontrolled psychiatric disease that could interfere with study participation 19. Fibromyalgia