Transforaminal Lumbar Interbody Fusion

This is a prospective, multicenter, randomized, controlled study evaluating Influx™ ProteiOS®, an allograft-derived growth factor product, in transforaminal lumbar interbody fusion (TLIF). Participants undergoing 1- to 2-level TLIF (L2-S1) are randomized 2:1 to receive ProteiOS or a control graft (local bone with optional cancellous chip augmentation, no ProteiOS). The primary objective is to determine whether the 12-month interbody fusion rate (assessed by CT using the Brantigan-Steffee-Fraser classification) with ProteiOS is non-inferior to control, using a 5-percentage-point non-inferiority margin. Patient-reported outcomes (ODI, VAS, EQ-5D-5L), safety, and healthcare utilization are also assessed. A separate exploratory cohort at one study site will evaluate the same outcomes in participants undergoing anterior lumbar interbody fusion (ALIF) with or without ProteiOS, without formal hypothesis testing.