Objective: Statins stimulate bone formation by inducing the expression of bone morphogenetic proteins (BMP-2). The aim of our study was to investigate the effects of orally administered simvastatin on spinal fusion in rats.
Methods: Twenty rats were randomized into a spinal fusion group (SF) (n=10) or a spinal fusion and oral simvastatin administered group (SFS) (n=10). A spinal fusion was performed between L4-L6 representing two levels. Simvastatin (120 mg/kg/day) was administered orally in the SFS group. The rats were killed at the end of the 12 week study period.
Results: Manual palpation revealed two moderate fusions in the SF group. The SFS group did not reveal any signs of pseudoarthrosis. An average three-point bending force causing failure of fusion revealed results of 148.80±39.403 Newtons and 123.80±28.479 Newtons in SFS and SF groups, respectively (p>0.05). Histological examination revealed better fusion grades in the SFS group (mean: 9.30±0.949) than in the SF group (mean: 6.80±2.044) (p=0.003). Radiographic examination revealed Grade C fusion in two levels and Grade A fusion in 18 levels in the SF group. In the SFS group, Grade C fusion was detected in one level and Grade A fusions in 19.
Conclusion: Our results suggest that simvastatin can promote spinal fusion and can be used as an adjunct to spinal fusion procedures in an elderly population with high cholesterol levels.