Spinal Adverse Events Severity System, version 2 (SAVES-V2): inter- and intraobserver reliability assessment

OBJECTIVE Reporting of adverse events (AEs) in spinal surgery uses inconsistent definitions and severity grading, making it difficult to compare results between studies. The Spinal Adverse Events Severity System, version 2 (SAVES-V2) aims to standardize the classification of spine surgery AEs; however, its inter-and intraobserver reliability are unknown. The objective of this study was to assess inter-and intraobserver reliability of the SAVES-V2 grading system for assessing AEs in spinal surgery. METHODS Two multinational, multicenter surgical study groups assessed surgical case vignettes (10 trauma and 12 degenerative cases) for AE occurrence by using SAVES-V2. Thirty-four members of the Spine Trauma Study Group (STSG) and 17 members of the Degenerative Spine Study Group (DSSG) participated in the first round of case vignettes. Six months later, the same case vignettes were randomly reorganized and presented in an otherwise identical manner. Inter-and intraobserver agreement on the presence, severity, number, and type of AE, as well as the impact of the AE on length of stay (LOS) were assessed using intraclass correlation (ICC), Cohen's kappa value, and the percentage of participants in agreement. RESULTS Agreement on the presence of AEs ranged from 97% to 100% in the 2 groups. Severity classification showed substantial interobserver (ICC = 0.75 for both groups) and intraobserver (ICC = 0.70 in DSSG, 0.71 in STSG) agreement. Judgments on the number of AEs showed high interobserver agreement and moderate intraobserver agreement in both groups. Both the STSG and DSSG had high intraobserver agreement on the type of AE; interobserver agreement for AE type was high in the STSG and fair in the DSSG. Agreement on impact of the AE on LOS was excellent in the DSSG and fair in the STSG. CONCLUSIONS There was good agreement on the presence, severity, and number of AEs in both trauma and degenerative cases in using the SAVES-V2. This grading system is a simple, reliable tool for identifying and capturing AEs in spinal surgery.