Evaluation of the IFuse Bedrock Technique in Association with Posterior Lumbosacral Fusion with Iliac Fixation.

This study evaluates a new spinal fusion technique called the iFuse Bedrock technique, which uses a specific implant to stabilize the sacroiliac joint (the joint between the spine and pelvis) during complex lower back fusion surgeries. You may be eligible if: - You are 18 years or older - You are scheduled for open posterior lumbosacral fusion including L4, L5, and S1 with sacroiliac joint fusion and iliac fixation - You have at least one iFuse-3D implant placed using the Bedrock technique - You had positive pain provocation tests for sacroiliac joint dysfunction - You have degenerative sacroiliac joint disease requiring fusion You may NOT be eligible if: - You have severe osteoporosis (DEXA score above -3) - You have had prior sacroiliac joint fusion or S2-iliac surgery - You are not receiving the iFuse-3D implant or it is not placed using the Bedrock technique - You have neurological conditions, local or systemic infection, or allergy to implants - You are pregnant or planning pregnancy - You are a prisoner or ward of the state Talk to your doctor to see if this trial is right for you.