Objective: To determine whether a biphasic calcium phosphate (BCP) ceramic supplemented with fresh autologous bone marrow (BMA) can give rise to adequate bone to achieve a vertebral fusion mass.
Materials and methods: A prospective nonrandomized, radiographic study on 35 patients with posterolateral fusion using rigid transpedicular instrumentation for degenerative lumbar disease. At least 2-year follow-up. On the left side: autologous bone graft obtained from decompression. On the right side: a mixture of BCP and fresh autogenous bone marrow from the right iliac crest. Single-level fusion in 22 patients and two or more levels in 13. Patients assessed with x-rays and computed tomography by an orthopedic surgeon and an independent radiologist. Fusion mass was considered "good" when there was a continuous block of bone without radiolucent areas. No intersegmental bony bridging fusion was considered "poor" mass. McNemar, Fisher, and kappa tests were used for statistical analysis.
Results: The interobserver agreement (kappa) had an average of 0.75 for the fusion masses. The interobserver average in the radiologic evaluation of ceramic resorption was 0.68. No differences between smokers and nonsmokers were found. Plain radiography findings: good left fusion masses (autologous bone) in 31 patients and poor in 4; good right masses (BMA plus BCP) in 31 patients and poor in 4 (P > 0.05). Computed tomography evaluation: good left fusion masses in 28 patients and poor in 7; good right fusion masses in 31 patients and poor in 4 (P > 0.05). One patient was reoperated, allowing biopsies to be performed: compact bone tissue was observed around hydroxyapatite in the right fusion mass.
Conclusions: The differences detected between right-side and left-side masses are not statistically significant. This indicates that, BMA and BCP, when mixed, behave like composite grafts and are able to generate sufficient bone mass for arthrodesis when a rigid instrumentation is used. However, a larger number of cases and longer follow-up are needed to generalize the indication.