Role of a Novel, Fresh-Frozen Cellular Bone Allograft in Lumbar Interbody Spinal Fusion: A Retrospective, Matched-Cohort Study.

Abstract

Retrospective matched-cohort study. To evaluate the clinical efficacy, safety, and economic impact of a novel cellular bone allograft (PrimaGen Advanced Allograft; CBA-P) used in combination with recombinant human bone morphogenetic protein-2 (rhBMP-2) for short-segment lumbar interbody fusion. Osteobiologic grafts are increasingly used to optimize lumbar interbody fusion outcomes. Recombinant human bone morphogenetic protein-2 (rhBMP-2) improves fusion rates but is costly and associated with complications. Cellular bone allografts (CBAs) aim to enhance fusion by providing a bony scaffold, growth factors, and viable cells, but their clinical and economic benefit remains unclear. We retrospectively assessed 100 adults who underwent 1- or 2-level posterior or transforaminal lumbar interbody fusion between 2017 and 2023. Fifty patients received CBA-P with rhBMP-2 (experimental cohort), and 50 matched controls received rhBMP-2 with standard-of-care demineralized bone matrix and/or allograft bone powder. Matching was based on age decade, sex, and fusion level. The primary outcome was interbody fusion at 12 and 24 months, assessed using a validated radiograph measurement platform. Secondary outcomes included revision surgery, complications, pain scores, and per-case osteobiologic cost. Fusion rates were similar between cohorts at 12 months (95.7% vs. 89.1%, P=0.27) and 24 months (100% vs. 89.5%, P=0.49), with comparable revision and complication rates. Estimated blood loss (364.4 vs. 232.9 mL, P<0.001) and 6-month pain scores (P=0.03) were higher in the experimental cohort. CBA-P use significantly increased per-case osteobiologic cost ($9478 vs. $5252, P<0.0001). Use of CBA-P with rhBMP-2 did not improve fusion rates, reduce complications, or enhance pain outcomes, yet markedly increased surgical cost. These findings do not clearly support the routine use of CBA-P alongside rhBMP-2 in short-segment lumbar interbody fusion and highlight the need for well-designed prospective studies to define its standalone clinical value. Level III.