Fig. 2
(a) diagram of preoperational sagittal measurements; (b) An actual preoperational measurement, the sagittal OLF area was 59.1 mm2, the sagittal canal area was 117.2 mm2, and the saggital invasive proportion was 50.43%; (c) diagram of postoperational sagittal measurements; (d) An actual postoperational measurement, the area of OLF was 0 mm2, the area of canal was 117.2 mm2, and the invasive proportion was 0%