Fig. 4.

Incidence of revision surgery according to postoperative lordosis distribution index (LDI). Cumulative incidence of revision surgery, using 1-Kaplan Meier survival analyses, according to postoperative LDI groups showed a significant difference in revision between groups. The lowest incidence of revision was found in patients with “normal” postoperative LDI (LDI 50–80). Revision surgery was defined as revision for any reason except hematoma, infection, or wound dehiscence. The provided p-value is derived from an unweighted log-rank test (p=0.030). Fleming-Harington weighted log-rank test: p=0.036. LDI ratios refer to the following LDI groups: 50–80, normal distribution; < 50, hypolordotic maldistribution; > 80, hyperlordotic maldistribution.