MagnetOs Flex Matrix Compared to Trinity Elite Mixed With Local Autograft in Patients Undergoing up to Four-level Instrumented Posterolateral Fusion

This study compares MagnetOs Flex Matrix (a synthetic bone graft substitute) with a traditional bone graft in patients undergoing lumbar spinal fusion surgery at up to four vertebral levels, to evaluate which promotes better bone fusion and recovery. You may be eligible if: - You are 18 years of age or older - You have leg and/or back pain requiring spinal fusion surgery in up to four lumbar levels (T11–S1) - You have tried conservative treatments (physical therapy, injections, etc.) for at least 3 months without adequate relief - You are able to provide informed consent You may NOT be eligible if: - You need more than four spinal levels fused - You have had prior fusion surgery at the levels being treated - You are pregnant or plan to become pregnant within 12 months - You have an active infection, cancer, or severe metabolic bone disease (like Paget's disease) - You have a history of active malignancy - You have a substance abuse issue or psychiatric disorder that could affect healing - You are involved in spinal-related litigation Talk to your doctor to see if this trial is right for you.