Soufiane Ghailane1, Houssam Bouloussa2, Vincent Challier2, Claudio Vergari3, Go Yoshida2, Ibrahim Obeid2, Louis Boissière2, Jean-Marc Vital2, Simon Mazas2, Pierre Coudert2, Olivier Gille2. 1. Department of Spinal Surgery Unit 1, Université de Bordeaux, Bordeaux University Hospital, C.H.U Tripode Pellegrin, Place Amélie Raba Léon, 33076 Bordeaux, France. Electronic address: soufiane.ghailane@gmail.com. 2. Department of Spinal Surgery Unit 1, Université de Bordeaux, Bordeaux University Hospital, C.H.U Tripode Pellegrin, Place Amélie Raba Léon, 33076 Bordeaux, France. 3. University of Exeter, School of Physics and Astronomy, Exeter, United Kingdom.
Abstract
STUDY DESIGN: Inter- and intraobserver reliability study. OBJECT: To assess the reliability of a new radiographic classification of degenerative spondylolisthesis of the lumbar spine (DSLS). SUMMARY OF BACKGROUND DATA: DSLS is a common cause of chronic low back and leg pain in adults. To this date, there is no consensus for a comprehensive analysis of DSLS. The reliability of a new DSLS classification system based on sagittal alignment was assessed. METHODS: Ninety-nine patients admitted to our spinal surgery department for surgical treatment of DSLS between January 2012 and December 2015 were included. Three observers measured sagittal alignment parameters with validated software: segmental lordosis (SL), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sagittal vertical axis (SVA). Full body low-dose lateral view radiographs were analyzed and classified according to three main types: Type 1A: preserved LL and SL; Type 1B: preserved LL and reduced SL (≤5°); Type 2A: PI-LL ≥10° without pelvic compensation (PT <25°); Type 2B: PI-LL ≥10° with pelvic compensation (PT ≥25°); Type 3: global sagittal malalignment (SVA ≥40 mm). The three observers classified radiographs twice with a 3-week interval for intraobserver reproducibility. Interobserver reproducibility was calculated using Fleiss κ and intra-class coefficient. Intraobserver reproducibility was calculated using Cohen κ. RESULTS: Mean age was 68.8 ± 9.8 years. Mean sagittal alignment parameters values were the following: PI: 60.1° ± 12.7°; PI-LL was 12.2° ± 13.9°, PT: 24.7° ± 8.5°; SVA: 44.9 mm ± 44.6 mm; SL: 16.6° ± 8.4°. Intraobserver repeatability showed an almost perfect agreement (ICC > 0.92 and Cohen κ > 0.89 for each observer). Fleiss κ value for interobserver reproducibility was 0.82, with percentage agreement among observers between 88% and 89%. CONCLUSION: This new classification showed an excellent inter- and intraobserver reliability. This simple method could be an additional sagittal balance tool helping surgeons improve their preoperative DSLS analysis.
STUDY DESIGN: Inter- and intraobserver reliability study. OBJECT: To assess the reliability of a new radiographic classification of degenerative spondylolisthesis of the lumbar spine (DSLS). SUMMARY OF BACKGROUND DATA: DSLS is a common cause of chronic low back and leg pain in adults. To this date, there is no consensus for a comprehensive analysis of DSLS. The reliability of a new DSLS classification system based on sagittal alignment was assessed. METHODS: Ninety-nine patients admitted to our spinal surgery department for surgical treatment of DSLS between January 2012 and December 2015 were included. Three observers measured sagittal alignment parameters with validated software: segmental lordosis (SL), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), and sagittal vertical axis (SVA). Full body low-dose lateral view radiographs were analyzed and classified according to three main types: Type 1A: preserved LL and SL; Type 1B: preserved LL and reduced SL (≤5°); Type 2A: PI-LL ≥10° without pelvic compensation (PT <25°); Type 2B: PI-LL ≥10° with pelvic compensation (PT ≥25°); Type 3: global sagittal malalignment (SVA ≥40 mm). The three observers classified radiographs twice with a 3-week interval for intraobserver reproducibility. Interobserver reproducibility was calculated using Fleiss κ and intra-class coefficient. Intraobserver reproducibility was calculated using Cohen κ. RESULTS: Mean age was 68.8 ± 9.8 years. Mean sagittal alignment parameters values were the following: PI: 60.1° ± 12.7°; PI-LL was 12.2° ± 13.9°, PT: 24.7° ± 8.5°; SVA: 44.9 mm ± 44.6 mm; SL: 16.6° ± 8.4°. Intraobserver repeatability showed an almost perfect agreement (ICC > 0.92 and Cohen κ > 0.89 for each observer). Fleiss κ value for interobserver reproducibility was 0.82, with percentage agreement among observers between 88% and 89%. CONCLUSION: This new classification showed an excellent inter- and intraobserver reliability. This simple method could be an additional sagittal balance tool helping surgeons improve their preoperative DSLS analysis.