Introduction
Recently, Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E. coli-derived rhBMP-2) has been increasingly applied to different types of spinal surgeries and reported to achieve successful fusion. This pilot study of E. coli-derived rhBMP-2 aimed to evaluate the clinical efficacy of enhancing solid bony union and safety regarding rhBMP-2-related complications in patients undergoing posterior spinal fusions for unstable vertebral fractures for the first time.
Methods
This study included ten consecutive patients undergoing spinal surgery using E. coli-derived rhBMP-2 with more than one year of follow-up. Radiologic outcomes included the radiographic union and local kyphotic angle, anterior vertebral height, and vertebral wedge angle. Clinical outcomes included 10-point numerical rating scale (NRS) for back and leg pain and Oswestry Disability Index (ODI) scores as patient-reported outcomes.
Results
The average time of radiographic union was 99.9 ± 45.4 (62–192) days, and the mean follow-up period was 15.5 ± 3.7 months. Anabolic agents, such as teriparatide and romosozumab, were used in nine (90%) patients with an average use of 5.2 ± 3.9 months. Radiologic parameters such as anterior vertebral height and vertebral wedge angle were significantly corrected postoperatively and at the last follow-up. Clinical outcomes other than NRS for leg pain were significantly improved after the surgery. In addition, four patients with preoperative neurologic deficits showed improved neurologic status.
Discussion
Combined with the anabolic agents, applying E. coli-derived rhBMP-2 to the fractured vertebral body could achieve earlier solid fusion around 100 days without any adverse events, which might decrease the loss of correction and obtain better clinical outcomes. This study suggested a new surgical option using rhBMP-2 in unstable spinal fractures. In addition, anabolic agents could help achieve earlier solid fusion. In advancing biomaterials and pharmaceuticals, surgical techniques could be changed for better clinical outcomes. However, further comparative studies with a large number of patients are needed to validate the advantage of this technique over other techniques and identify detailed surgical indications.