The effects of radiofrequency disc nucleoplasty on rabbit intervertebral disc tissue

PURPOSE: The aim of this study is to determine the rise in temperature and thermal damage after application of nucleoplasty on rabbit intervertebral discs. MATERIALS AND METHODS: Twenty seven (2.0-3.0 kg) male rabbits (New Zealand White Rabbit) were used in this study. 5 groups were created. The sham group(group1) was ony cannulated, , in the second and third groups level 2 single 542 J) and double(1084 J), in the fourth and fifth group level 4 single(1063 J) and double 2126 J) holes were created. 5 seconds before and 11 seconds after the procedure temperature was measured by thermocouple. Motor Function was determined using Drummond and Moore criteria; 1., 24. hours and 7., 14., 21., 28. th day after reperfusion. After 5 weeks intervertebral discs, endplates and neural tissue were examined macroscopically and microscopically. Kruskal-Wallis and Mann-Whitney U tests were used for comparison between the groups RESULTS: The sham group, the level 2 single (542 J) showed no neurological deficits while in the level 4 double group (2126J) paraplegia , microscopically increase in degeneration was encountered . There was no difference in temperatures between two groups.Pathological scores were : group1 1.00, group 2 (542 J) 1.00, group 3 (1084 J) 2.00, group 4 (1063 J) 2.83, group 5 (2126 J) 3.50 . CONCLUSION: The effectiveness of cervical nucleoplasty was attributed to the nonheatdriven process used in contrast to laser discectomy. The damage encountered after the application of high joule energy is attributed not to the direct effects but electrical damage which makes us think that low watts of energy should be used in cervical nucleoplasty.