Risk factors of revision operation and early revision for adjacent segment degeneration after lumbar fusion surgery: a case-control study

Sehan Park; Chang Ju Hwang; Dong-Ho Lee; Nam Yeop Kim; Hyun Wook Nam; Hyun Wook Kang; Choon Sung Lee; Cha Hyeong Ok; Jae Hwan Cho

doi:10.1016/j.spinee.2024.04.013

Risk factors of revision operation and early revision for adjacent segment degeneration after lumbar fusion surgery: a case-control study

Spine J. 2024 Apr 24:S1529-9430(24)00183-9. doi: 10.1016/j.spinee.2024.04.013. Online ahead of print.

Authors

Sehan Park¹, Chang Ju Hwang¹, Dong-Ho Lee¹, Nam Yeop Kim¹, Hyun Wook Nam¹, Hyun Wook Kang², Choon Sung Lee², Cha Hyeong Ok¹, Jae Hwan Cho³

Affiliations

¹ Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Pungnap-2-dong, Seoul, Republic of Korea.
² Department of Spine Surgery, St.Peter's Hospital, 2649, Nambusunhwan-ro, Gangnam-gu, Seoul, Republic of Korea.
³ Department of Orthopedic Surgery, Asan Medical Center, University of Ulsan College of Medicine, Pungnap-2-dong, Seoul, Republic of Korea. Electronic address: spinecjh@gmail.com.

PMID: 38663482
DOI: 10.1016/j.spinee.2024.04.013

Abstract

Background context: Adjacent segment degeneration (ASD) following lumbar fusion operation is common and can occur at varying timepoints after index surgery. An early revision operation for ASD, however, signifies a short symptom-free period and might increase the risk of successive surgeries.

Purpose: We aimed to elucidate the overall risk factors associated with revision surgeries for ASD with distinct attention to early revisions.

Study design/setting: Retrospective, case-control study.

Patient sample: The study included 86 patients who underwent revision operations for ASD after lumbar fusion in the revision group and 166 patients who did not for at least 5 years after index surgery.

Outcome measures: Sagittal parameters, Pfirrmann grading, facet degeneration grading, and disc space height (DSH) of adjacent segments were assessed.

Methods: Revision operations within 5 years postsurgery were defined as early revision. We compared the revision and no-revision groups as well as the early- and late-revision groups.

Results: The revision group demonstrated a significantly greater preoperative C7-S1 sagittal vertical axis (SVA) (p=.001), postoperative C7-S1 SVA (p<.001), and postoperative pelvic incidence (PI)-lumbar lordosis (LL) (p<.001) than those in the no-revision group. Preoperative DSH of the proximal adjunct segment (p=.001), postoperative PI-LL (p=.014), and postoperative C7-S1 SVA (p=.037) exhibited significant association with ASD in logistic regression analysis. The early-revision group had a significantly higher patient age (p=.001) and a greater number of levels fused (p=.030) than those in the late-revision group. Multivariate Cox regression analysis demonstrated that old age (p=.045), a significant number of levels fused (p=.047), and a narrow preoperative DSH of the proximal adjacent level (p=.011) were risk factors for early revision.

Conclusions: Postoperative sagittal imbalance, including significant PI-LL and C7-S1 SVA were risk factors for revision operation for ASD but not for early revision. These factors are likely to affect the long-term risk of revision operation due to ASD and thus are not considered risk factors for early revision. Narrow DSH of the proximal adjacent level increased the risks of both revision and early revision surgeries. Moreover, old age and a significant number of levels fused further increased the risk for early revision for ASD.

Keywords: Adjacent segment degeneration; Disc space height; Early revision; Lumbar fusion operation; Revision surgery; Risk factors; Sagittal parameters; Survival analysis.