Introduction: The use of mesenchymal stem cell (MSC) containing allografts, also known as cellular bone matrices (CBMs) has recently increased in popularity and is thought to account for greater than 17% of all bone grafts and bone graft substitutes used in spinal fusion surgery. While the claim of CBMs containing osteogenic cells with osteoinductive cytokines is an attractive one, little is known about their clinical success. The purpose of this study is to report on the radiographic fusion rates in one- and two-level anterior cervical discectomy and fusion (ACDF) using a CBM.
Methods: 56 consecutive patients undergoing a one- or two-level ACDF for the treatment of degenerative cervical radiculopathy or myelopathy were prospectively followed. Patients were fused using a structural interbody allograft packed with a CBM. Fusion was assessed at 6 months with thin slice computerized tomography (CT). Fusion was defined as evidence of bridging trabeculae between the operated levels. If segments were not fused at 6 months, flexion/extension X-rays were taken at 1 year to evaluate for boney fusion. Symptomatic patients at 1 year underwent a second CT scan, and those with radiographic evidence of pseuoarthrosis had a posterior fusion.
Results: 56 patients underwent ACDF at 83 levels. 29 patients (52%) underwent 1-level fusion and 27 (48%) underwent 2-level fusions. 45 of 56 (80%) patients had radiographic evidence of complete fusion at 6 months follow-up. Age, gender, diabetes mellitus and smoking were not associated with fusion rates in both 1- and 2-level fusions (p>0.05). At one-year follow-up, 51 of 56 (91%) patients had evidence of complete fusion. Posterior fusion was performed on 3 (5%) patients who were symptomatic at one-year. One (1.8%) patient did not fuse but was asymptomatic. There were no graft related complications.
Conclusions: This is the first non-industry sponsored report on radiographic fusion rates in 1- and 2-level ACDF using a CBM. While the fusion rates in this study are high, they are equivalent to fusion rates using non-stem cell containing allografts. CBMs may be a promising bone augmentation technology in spinal fusion surgery, however, their efficacy above that of standard allografts remains inconclusive.
Patient Care: This study sheds light on the use and clinical effectiveness of mesenchymal stem cell allografts - a novel bone graft substitute technology
Learning Objectives: At the end of this session, participants should be able to: 1) describe fusion rates using stem cell allografts, 2) become aware of these novel products and their clinical efficacy