Sample size calculation
INFLAMMATION
The sample size was calculated based on the unpaired numerical analytical research formula. The standard deviation in the unpaired group was the combined standard deviation of the two groups. Type I error was set at 5%, one-way hypothesis so that Za = 1.64. The type II error was set at 10%, and Zb = 1.28. Based on IL-6 (S = 13.1; X1-X2 = 13) and IL-10 (S = 8.6; X1-X2 = 9) concentrations [Za = standard derivative alpha.Zb = standard derivative beta.S = the combined standard deviation of the compared groups.X1 – X2 = the minimum difference in the mean that is considered significant.There are a limited number of studies that utilize IL-6 and IL-10 as markers of inflammation, especially in patients undergoing spinal surgery. In this study, we used Amin et al.’s study [This study would require a sample size of 18 for each group. We included 18 participants in each group. A total of 40 participants enrolled in this study, with comparable allocation to two arms, allowing for a drop-out of 10%.