Performance of Porous Pelvic Fixation Implants in Multilevel Spine Fusion Surgery

Study Design: A multicenter, prospective and retrospective, real-world evidence study conducted at eight US sites (PAULA, NCT05640908). Objective: To assess the one-year interim results of the clinical performance and safety of 3D-printed porous pelvic fixation implants (PPFI) in adult patients undergoing multilevel (≥4 levels) spinal fusion with pelvic fixation. Summary of Background Data: Adult spine deformity (ASD) is a prevalent cause of low back pain and disability among older adults. Complex multilevel spinal fusion with pelvic fixation is commonly performed to restore alignment and reduce hardware failure. Despite advancements in fixation techniques, pelvic construct failure remains frequent, contributing to high rates of mechanical complications and revision surgeries. Materials and Methods: Adults scheduled for spinal fusion with pelvic fixation using a PPFI were enrolled prospectively or retrospectively. Eligible patients were adults undergoing lumbar fusion of ≥4 levels with pelvic fixation using PPFIs. Collected assessments consisted of patient-reported outcomes (PROs), x-rays, and advanced imaging (CT scan, MRI), as per standard of care, and adverse events at 6, 12, and 24 months postprocedure. Statistical analyses included the Fisher exact test and general linear modeling. Results: A total of 122 patients were treated (36 primary and 86 revision fusions). Thirty-six (28.8%) of cases were primary surgery, and 89 (71.2%) were revision surgeries. The mean (SD) age at study entry was 64.1 (10.4) years, BMI 30.8 (6.0), and 56.8% female. Four device-related adverse events (3.2%) were reported, comprising one primary PPFI failure, two distal rod fractures, and one case of PPFI malposition. At 12 months, mean low back pain decreased from 7.2 to 4.5 points, and mean Oswestry Disability Index improved from 55.2 to 39.6 points, representing clinically meaningful improvements. Conclusion: PPFI demonstrated a low rate of primary implant-related failure and favorable short-term clinical outcomes in patients undergoing complex multilevel fusion for ASD. Longer-term follow-up and radiographic data are needed to determine whether these advantages persist over time. Level of Evidence: Level III.