Experimental disk degeneration model using radiofrequency application

EXPERIMENTAL DISK DEGENERATION MODEL USINGRADIOFREQUENCY APPLICATIONPURPOSE: To create a standard animal model in which radifrequency is applied torabbits to demonstrate the biochemical and histopathological features of diskdegeneration.METHODS: 18 rabbits were used in this study. The control group consisted of tworabbits and remaining 16 rabbits constituted the study group. The L4-5 level waspunctured with a 19g needle and RF energy was applied to L3-4 (level 3), and L2-3 (level2) levels to the intervertebral disks in the study group. Six rabbits were sacrified on the15.day and the intervertebral disks were taken for histopathological examination. Theremaining 10 rabbits in the study group were sacrified on the 30.day and thehistopathological and biochemical examinations were performed. Histopathologicallycollagen structure, neovascularization and chondrocytes were examined, andbiochemically water content of the nucleus pulposus, amount of type II collagen andsulfated glucosaminoglicans were measured. The results were compared using Kruskal -Wallis variance analysis and Mann-Whitney-U test.RESULTS: The histopathological examination of the six rabbits that were sacrified onthe 15.day revealed that the permanence of the annulus fibrosis was interrupted and thehomogen structure was lost. At the same time the condrocytes were observed to appear ingroups and fibrous band which consisted of irregular collagen fibers developed in the NP.All three procedures applied supported disk degeneration. The histopathologicalexamination of the intervertebral disks of the rabbits that were sacrified on the 30th dayrevealed similar results while neovascularization was observed in the RF appliedintervertbral disks. Biochemically all three groups demonstrated decrease in watercontent (statistically significant in group three) and type II collagen (statisticallysignificant in group two) in the NP. There were no changes in the amount of sGAG.CONCLUSION: In the guidance of biochemical and histopahological findings; astandard, acceptable and easily applicable animal model was created.KEY WORDS: Intervertebral disk degeneration, radiofrequency, animal model2