Evaluation of the Effect of Granulocyte Colony Stimulating Factor on Spinal Fusion in a Rat Model of Spinal Surgery

To evaluate the effects of granulocyte colony stimulating factor (G-CSF) on spinal fusion through manual palpation, radiological examinations, and histopathological analyses in a rat model.

A total of 21 rats were evaluated in this study. The rats were divided into the following three groups, each consisting of seven rats: preoperative G-CSF, postoperative G-CSF, and a control group. L4-L5 posterolateral fusion was performed in all three groups. The preoperative G-CSF group received 5 μg/kg G-CSF subcutaneously for 5 days in the preoperative period, while the postoperative G-CSF group received the same intervention in the postoperative period. No additional postoperative procedures were performed in the control group. All rats were euthanized at 6 weeks, and the fusion site was evaluated using manual palpation, radiological examinations, and histopathological analyses.

According to the classification of subjects according to manual examination, preoperative and postoperative G-CSF groups had significantly higher rates of "single prominent callus formation + fusion" (p < 0.05). When direct radiography scores were evaluated, the number of subjects with "unilateral solid new bone density - contralateral nonsolid bone density" was significantly greater in the preoperative G-CSF group, while "bilateral solid new bone densities" was more prevalent in the postoperative G-CSF group (p < 0.05). In regards to histopathological scores, the number of subjects rated as "fibrocartilage tissue is more than bone tissue" was higher in the preoperative G-CSF group, the number of subjects rated as-bone tissue is more than fibrocartilage tissue" was higher in the postoperative G-CSF group, and the number of subjects rated as "fibrous tissue is more than fibrocartilage tissue" was greaterin the control group (p=0.01). Preoperative and postoperative G-CSF groups had significantly higher manual examination, radiological, and histopathological scores and greater volume of new bone formation on 3D CT compared to the control group (p < 0.05).

The results of our study demonstrated that preoperative and postoperative administration of G-CSF had positive effects on spinal fusion in a rat model.