Anterior Cervical Discectomy and Fusion Using Escherichia coli-Derived Recombinant Human Bone Morphogenetic Protein-2: A Pilot Study

Background: Recombinant human bone morphogenetic protein-2 (BMP-2) is an osteoinductive growth factor widely used in ortho-pedic surgery; it is also known to be associated with postoperative airway compromise or dysphagia when applied to anterior cer-vical discectomy and fusion (ACDF). However, there have been no reports on ACDF using Escherichia coli-derived BMP-2 (E.BMP-2) with hydroxyapatite (HA). This pilot study aimed to investigate the potential efficacy and safety of E.BMP-2 using HA as a carrier in ACDF prior to designing a larger-scale prospective study.Methods: Patients eligible for inclusion were those who underwent ACDF using 0.3 mg of E.BMP-2 with HA per segment for de-generative cervical disc disease between August 2019 and July 2020 and had at least 1 year of follow-up. Fusion rates were ana-lyzed using computed tomography or flexion-extension radiographs. Visual analog scales for neck pain and arm pain and neck dis-ability index were measured preoperatively and the final follow-up. In cases of cervical spondylotic myelopathy, modified Japanese Orthopaedic Association scores were also evaluated. Postoperative complications such as airway compromise, dysphagia, wound infection, neurologic deficit, hoarseness, heterotopic ossification, seroma, and malignancy were investigated.Results: A total of 11 patients and 21 segments were analyzed. All clinical outcomes significantly improved at the final follow-up compared with the preoperative indices (p < 0.05). Only 1 case of dysphagia and no cases of airway compromise, wound infection, neurologic deficit, hoarseness, heterotopic ossification, seroma, or malignancy were observed during the follow-up period. Of the 21 segments, 15 segments showed solid fusion at 3 months after surgery, 4 segments at 6 months, and 1 segment at 12 months. Only 1 segment showed pseudoarthrosis, resulting in a fusion rate of 95.2%. Conclusions: The outcomes of ACDF could be enhanced using 0.3 mg of E.BMP-2 with HA per segment. Based on this study, larger-scale prospective studies can be conducted to evaluate the efficacy and safety of E.BMP-2 in ACDF.