Glenn R. Buttermann, MD,MS: No relevant disclosure to display
Introduction. Anterior cervical discectomy and fusion (ACDF) is a proven treatment for patients with disc herniation or spondylytic conditions with significantly improved long-term outcomes. However, pseudarthrosis results in less favorable outcomes. Fusion success depends, in part, on type of material used for bone graft.
Aims/Objective. Assess the fusion rate and improvement in clinical outcomes for ACDF using 4 types of bone graft (autograft, allograft, modified ceramic, and bone morphogenic protein (BMP)).
Methods. Consecutive patients from January 2018 through Dec 2021 who had elective anterior cervical diskectomy and fusion (ACDF) for degenerative conditions are the basis for this study. All ACDF used a radiolucent interbody device and one of 4 types of bone grafts: iliac crest bone autograft (IBG), demineralized bone matrix (Progenix, DBM), enhanced ceramic (i-Factor), or BMP (n = 22, most often used for those with increased risk of non-union: revision for a prior fusion (n=6), adjacent level ACDF (n= 7), or if >2 levels fused (n=7)). Clinical outcome assessment (neck and arm VAS, NDI) was collected prospectively and followed for >2 years which was then retrospectively reviewed. The radiographic criteria used for determining solid fusion were strict: CT imaging demonstrating cancellous bone throughout the interbody space without interruption, < 2 mm of flexion-extension spinous process instability on sagittal x-rays at 1 year postoperatively. If either of these criteria were not attained at any surgical level, then the patient was considered to have a nonunion.
Results. Of 115 patients who had ADCF, 93 (81%) had complete data including the imaging criteria. The mean age was 59 yo of which 58% female. Using the strict criteria for a fusion described above, the nonunion rate for all 93 patients was 24%. There were no differences in age or number of levels fused between solid vs pseudo groups. Analysis by bone graft type found the nonunion rate for: IBG (n = 34) was 21%, (DBM, n = 16) was 56%, enhanced ceramic (n = 17) was 21%, and BMP (n = 22) was 9%.
Patient outcomes found those with a solid ACDF had significantly greater improved outcomes for neck and arm VAS and NDI compared to those with non-union (Table), and were taking less opioid medication at one year postoperatively. Analysis by graft type found neck VAS and NDI improvement was best for the ceramic group and least for the DBM group (which also had the highest non-union rate) during both the first and second year postoperative. At 2 year follow-up, the DBM group was taking twice the amount of opioids.
Conclusion. Outcomes had greater improvement in those with a sold fusion. Thighest fusion rate was in the BMP group. Progenix is the least expensive but has a high nonunion rate and only a modest improvement in outcomes.
