Evaluation of Autologous Platelet Concentrate for Intertransverse Process Lumbar Fusion

Data on the role of platelet concentrate (PC) in spinal fusion are limited. Using the New Zealand white rabbit model, we compared fusion rates at L5–L6 using 2 different volumes (1.5 cm³, 3.0 cm³) of iliac crest autograft with and without PC (4 groups total, 10 animals in each). PC was collected from donor rabbits and adjusted to a concentration of 1x106 platelets/mL. Bone growth and fusion were evaluated using biomechanical, radiographic, and histologic testing. At 1.5 cm³, autograft alone had a 29% fusion rate, compared with autograft plus PC, which had a 57% fusion rate (P = .06). At 3.0 cm³, the fusion rate approached 90% in both groups. Radiologic fusion had a 70% correlation with biomechanical test results. Huo/Friedlaender scores were 4.3 (SD, 2.9) for 1.5-cm³ autograft alone; 5.0 (SD, 3.5) for 1.5-cm³ autograft plus PC; 4.7 (SD, 2.5) for 3.0-cm³autograft alone; and 7.7 (SD, 0.6) for 3.0-cm³ autograft plus PC. For 1.5-cm³ autograft, a trend toward improvement in biomechanically defined fusion was found when PC was added, which suggests that, when the amount of bone graft is limited, PC may function as a graft extender in posterolateral fusion. At higher volumes of bone graft, no appreciable difference was noted between groups. Although radiography revealed fusion masses, the technique was not useful in identifying pseudarthrosis. On histologic analysis, adding PC seemed to result in more mature bone at both volumes, with the most mature bone in the group with 3.0-cm³ autograft plus PC.