Evaluation of the Fusion Rate and Safety of Escherichia coli-Derived rhBMP-2 in Transforaminal Lumbar Interbody Fusion for Patients with Degenerative Lumbar Disease: A Prospective, Multicenter, Single-Arm Trial

Abstract

Background: Few studies have documented the viability of E. coli-derived recombinant human bone morphogenetic protein-2 (rhBMP-2) in transforaminal lumbar interbody fusion (TLIF). This study aimed to assess the safety and fusion rate of rhBMP-2 in TLIF. Methods: The study was conducted as a prospective, multicenter, single-arm trial, and 30 patients needing one- or two-level TLIF were enrolled. Fusion rate was assessed using the 12-month interbody fusion rate on CT. Postoperative problems, including seroma, radiculitis, and ectopic bone formation, which have been documented as risks associated with rhBMP-2 in prior studies, were recorded. Results: The study demonstrated fusion outcomes in all instances at 52 and 104 weeks post-surgery. Significant improvements were observed in clinical outcomes, with ODI, SF-36, and VAS scores, all achieving statistical significance (p < 0.0001). No perioperative adverse events requiring reoperation were reported, and there were no incidences of seroma, radiculitis, cage migration, grafted bone extrusion, postoperative neurologic deficit, or deep wound infection. Conclusions: The study demonstrates the high safety and efficacy in inducing bone fusion of E. coli-derived rhBMP-2 in TLIF, with a notable absence of adverse postoperative complications. Trial registration: This study protocol was registered at Korea Clinical Research Information Service (number identifier: KCT0004738) on July 2020.

Keywords: fusion rate; lumbar; rhBMP-2; transforaminal lumbar interbody fusion.

Figure 1

Description of the process of soaking rhBMP-2 in a TLIF cage. (a) Place Excelos Inject on the bottom of the window within the cage. (b) Fill the cage with HA-containing bone graft material soaked with rhBMP-2 at a dose of 0.5 mg to 1.0 mg per fusion segment. (c) To fix the graft material in the cage, apply the remaining Excelos Inject to the surface covered with the bone graft material. (d) Mold to fit the shape of the cage to prevent leakage when inserted into the interbody space. Abbreviations: rhBMP-2—recombinant human bone morphogenetic protein-2; HA—hydroxyapatite.

Figure 2

Representative plain X-ray and CT slices of a 72-year-old man who underwent 1 level TLIF. (a) Plain X-ray at 52 weeks after surgery, Grade I according to Bridwell classification (fused with remodeling and trabeculae present); (b–d) Grade II, which refers to partial fusion where the allografts cortex joins with the endplate in CT sagittal and coronal view. Abbreviations: CT—computed tomography.