Spss statistic for windows version 22

Kaplan-Meier survival curves and log-rank tests were done to compare the time to coverage pre- and post-integration. Bivariate-statistical analyses were utilized to compare the pre- vs. post-integration, early vs. late, and primary vs. secondary groups against demographic, medical history, treatment, and complication variables. Student’s t-test was used for normal, continuous variables, and the Mann-Whitney U test for non-normal, continuous variables. Chi-square and Fisher’s exact tests were used for categorical variables as appropriate. Tests were performed using two sided p-values at alpha = 0.05. All statistical tests were performed using a standard software package (IBM SPSS Statistic for Windows, Version 22.0, Armonk, NY). The STROBE (Strengthening the Reporting of Observational Studies in Epidemiology) statement was used as a guideline for reporting this paper.^{[20 (link)]}

Abstracted data was used to recreate 2×2 tables and calculate SN, SP, +LR, and −LR. If studies used 3×2 tables, including a third “equivocal” result, 2×2 tables were created by conservatively adding the equivocal results with a true injury to the FN cell and those without injury into the FP cell.^{20 (link)} We also analyzed thoracic or lumbar injury subgroups. Data was preferentially abstracted based on the presence of injuries using individual patients as the population. Results presenting individual vertebrae as the population (e.g. fractured vs. unfractured vertebrae), were analyzed separately. If studies used multiple observers and calculated SN and SP based on mean averages, these values were used to recreate 2×2 tables. When greater than one study assessed the same index test, we computed meta-analysis estimates using MetaDiSc (Hospital Univeritario Ramon y Cajal, Madrid, Spain) and forest tree plots for SN, SP, +LR, and −LR using a random-effects model.^{21 (link)} Pretest probability (prevalence) was estimated using a weighted average. The DerSimonian-Laird random effects model was used to calculate interstudy heterogeneity amongst pooled SN and SP using the index of inconsistency (I²). ^{22 (link),23 (link)} QUADAS-2 between-rater agreement was quantified using Cohen’s kappa (κ) with IBM SPSS Statistic for Windows, Version 22.0 (Armonk, NY).