Fig. 2

Study protocol. Of the 314 women whose abdominal wall-sacral distance (SAD) was measured, 287 were aged ≥ 65 years and were divided into two groups: 65–74-year and ≥ 75-year group; each group was further divided by a median SAD of 160 mm. ES group: 65–74-year-old patients with SAD < 160 mm; EL group: 65–74-year-old patients with SAD ≥ 160 mm; LS group: ≥75-year-old patients with SAD < 160 mm; LL group: ≥75-year-old patients with SAD ≥ 160 mm.