The effect of decortication on spinal fusion: an in vivo study in guinea pigs

Abstract

Objectives: Although spinal fusion is one of the most commonly used procedures in spinal surgery its properties are not fully known. The role of decortication is still not clear. In this animal model, we investigated the effect of decortication on spinal fusion. Methods: The study included 30 male guinea pigs (Cavia porcellus). Spine exposure was obtained through the right subperiosteal dissection between L2 and L6 in all animals, whereas the left sides were used as controls. The animals were assigned to three groups including decortication and autografting (group 1), decortication, instrumentation, and autografting (group 2), and instrumentation and autografting without decortication (group 3). All animals were sacrificed in the sixth postoperative week. The fusion mass was assessed by means of macroscopic evaluation, manual stress test, radiologic examination, and microscopic evaluation. Results: Based on segmentary evaluations, fusion was obtained in 80%, 95%, and 92.5% in groups 1, 2, and 3, respectively. The results were found statistically significant (Kruskal-Wallis nonparametric ANOVA test, p<0.001). Conclusion: The results show that decortication should be an essential step for spinal fusion if spinal instrumentation is not considered. However, in case of a stable instrumentation, decortication seems to exert no positive effect on the formation of spinal fusion.