Integral fixation titanium/polyetheretherketone cages for cervical arthrodesis: Two-year clinical outcomes and fusion rates using β-tricalcium phosphate or supercritical carbon dioxide treated allograft

CONTEXT: Despite increasing promising reports regarding composite titanium (Ti)/PolyEtherEtherKetone (PEEK) cages, further longer-term, quality research is required. Synthetic bone graft substitutes are another rapidly developing area of spinal surgical research. AIMS: The purpose of this study is to evaluate the outcomes of an integral fixation composite Ti/PEEK cage for anterior cervical discectomy and fusion (ACDF) and compare a synthetic bone graft substitute (β-tricalcium phosphate; [βTCP]) with allograft processed using supercritical fluid technology. METHODS AND DESIGN: Data from 195 consecutive patients were prospectively collected from a single centre. Indications were largely degenerative. Allograft and βTCP were used in a 3:1 randomization protocol. Patients were followed up for a minimum of 6 months and up to 48 months. Clinical outcomes included visual analogue scale and neck oswestry disability index. Radiographic outcomes included fusion rates, subsidence rates and implant complications. RESULTS: Graft sub-cohorts were largely comparable and included 133 and 52 patients in the allograft and βTCP sub-cohorts, respectively. Clinical outcomes overall significantly improved (P < 0.001), with no significant inter-cohort differences. There were no implant-related complications. Overall fusion rate was 94.1% (175/186). The allograft cohort produced a significantly greater fusion rate of 97.7% (126/129) compared to 77.6% (38/49) for the βTCP cohort (P = 0.001). CONCLUSIONS: This study demonstrates the viability of an integral fixation composite Ti/PEEK ACDF device in effectively and safely improving patient outcomes and achieving fusion. Allograft is more effective in achieving fusion compared to βTCP, though both were similarly efficacious in improving clinical outcomes.