Simvastatin improves spinal fusion in rats.

Abstract

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. 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. 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. 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.