Evaluation of the efficacy and safety of Escherichia coli-derived recombinant human bone morphogenetic protein-2 in transforaminal lumbar interbody fusion to treat degenerative spinal disease: a protocol of prospective, randomized controlled, assessor-blinded, open-label, multicenter trial

BACKGROUND: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has been widely used as an alternative bone graft in spine fusion surgery. However, clinical outcome such as effects and complications has not yet been revealed for transforaminal lumbar interbody fusion (TLIF). Although previous studies have reported some results, the evidence is weak. Therefore, the purpose of this trial is to evaluate the effectiveness and safety of Escherichia coli-derived rhBMP-2 combined with hydroxyapatite (HA) in TLIF. METHODS: This trial is designed as a prospective, assessor-blinded, open-label, multicenter, randomized controlled study. Participants will be recruited from six tertiary teaching hospitals. All randomized participants will be undergoing one- or two-level TLIF with rhBMP-2 (77 participants) as the active experimental group or with an auto-iliac bone graft (77 participants) as the control group. The primary interbody fusion rate outcome will be evaluated using computed tomography (CT) 12 months after surgery. The secondary outcomes will be as follows: clinical outcomes (visual analog scale score, EuroQol-5-dimensions-5-level score, Oswestry Disability Index score, and some surgery-related variables) and adverse effects (radiculitis, heterotrophic ossification, endplate resorption, and osteolysis). Radiological outcomes will be evaluated using simple radiography or CT. All outcomes will be measured, collected, and evaluated before surgery and at 12, 24, and 52 weeks postoperatively. DISCUSSION: This study will be the primary of its kind to evaluate the effectiveness and safety of E. coli-derived rhBMP-2 with HA in one- or two-level TLIF. It is designed to evaluate the equivalence of the results between rhBMP-2 with HA and auto-iliac bone graft using an appropriate sample size, assessor-blinded analyses, and prospective registration to avoid bias. This study will set up clear conclusions for using E. coli-derived rhBMP-2 with HA in TLIF. Trial registration: This study protocol was registered at Korea Clinical Research Information Service (https://cris.nih.go.kr; number identifier: KCT0005610) on 19 November 2020. And protocol version is v1.1, January 2022.