Effect of Clinical and Radiographic Degenerative Spondylolisthesis Classification on Patient-reported Outcomes and Spinopelvic Parameters for Patients With Single-level L4–L5 Degenerative Spondylolisthesis After Lumbar Fusion

Abstract

Study Design: Retrospective cohort study. Objectives: To determine whether preoperative clinical and radiographic degenerative spondylolisthesis (CARDS) classification is associated with differences in patient-reported outcomes and spinopelvic parameters after posterior decompression and fusion for L4–L5 degenerative spondylolisthesis (DS). Summary: The CARDS classification for lumbar DS, an alternative to the Meyerding system, considers additional radiographic findings such as disc space collapse and segmental kyphosis and stratifies DS into 4 radiographically distinct classes. Although CARDS has been shown to be a reliable and reproducible method for classifying DS, very few studies have assessed whether the CARDS types represent distinct clinical entities. Patients and Methods: A retrospective cohort analysis was conducted on patients with L4–L5 DS who underwent posterior lumbar decompression and fusion. Changes in spinopelvic alignment and patient-reported outcomes measures, including recovery ratios and percentage of patients achieving the minimal clinically important difference, were compared among patients in each CARDS classification 1-year postoperatively using analysis of variance or Kruskal-Wallis H with Dunn post hoc analysis. Multiple linear regression determined whether CARDS groups significantly predicted patient-reported outcomes measures, lumbar lordosis (LL), and pelvic incidence-lumbar lordosis mismatch (PI-LL) while controlling for demographic and surgical characteristics. Results: Preoperative type B spondylolisthesis predicted decreased improvement in “physical component and mental component score of the short form-12” compared with type A spondylolisthesis (β-coefficient = −5.96, P = 0.031) at 1 year. Significant differences were found between CARDS groups with regards to ΔLL (A: −1.63 degrees vs B: −1.17 degrees vs C: 2.88 degrees vs D: 3.19 degrees, P = 0.010) and ΔPI-LL (A: 1.02 degrees vs B: 2.09 degrees vs C: −2.59 degrees vs D: −3.70 degrees, P = 0.012). Preoperative type C spondylolisthesis was found to predict increased LL (β-coefficient = 4.46, P = 0.0054) and decreased PI-LL (β-coefficient = −3.49, P = 0.025) at 1 year compared with type A spondylolisthesis. Conclusions: Clinical and radiographic outcomes differed significantly by preoperative CARDS classification type for patients undergoing posterior decompression and fusion for L4–L5 DS. Level of Evidence: Level III.