The purpose of this prospective trial is to investigate ABM/P-15 bone graft versus traditional bone graft in patients undergoing surgery for Adult Spinal Deformity (ASD) in order to provide better clinical results through faster bone healing, no additional surgeries, fewer complications and thereby increase health-related quality of life. Main hypotheses: 1. The use of ABM/P-15 bone graft is superior to traditional bone graft treatment regarding the incidence of additional surgeries following index surgery for ASD Secondary hypotheses: 2. The investigators expect non-inferiority in patient reported outcome measures in the ABM/P-15 bone graft group compared to the control group 3. The investigators expect non-inferiority in the postoperative fusion rates (bone healing) evaluated on CT scans in the ABM/P-15 bone graft group compared to the control group 4. The investigators expect non-inferiority in postoperative incidence of asymptomatic pseudarthrosis in the ABM/P-15 bone graft group compared to the control group 5. The investigators expect non-inferiority in perioperative complications in ABM/P-15 bone graft group compared to the control group 6. The investigators expect the use of ABM/P-15 bone graft to be cost-efficient compared to the traditional treatment in the control group