Fig. 5.

Weibull regression model for revision surgery according to LDI groups. The Weibull regression model for accelerated, and proportional, relative event rates and relative extension survival time showed lowest incidence of revision surgery in patients with “normal” postoperative lordosis distribution index (LDI) defined as LDI of 50–80. Revision surgery was defined as revision for any reason except hematoma, infection, or wound dehiscence. LDI ratios refer to the following LDI groups: 50–80, normal distribution; < 50, hypolordotic maldistribution; > 80, hyperlordotic maldistribution.