| Popis: |
Background The anterior transpedicle screw technique for L5 and S1 is crucial for proper anterior lumbar interbody fusion. This study aimed to determine the projection, screw trajectory angle, and bone screw passageway length (BSPL) of the anterior transpedicle screw in L5 and S1, as well as the screw’s insertion regularity and the operating area that is safe for its insertion. Methods Forty patients with low back pain, all of whom had lumbar computed tomography scans available, were included in a retrospective analysis. Radiographic parameters were measured, including the distances from the projection to the upper endplate, lower endplate, and midline; the transverse and sagittal screws’ angles; and the BSPL. Ten fresh adult cadaveric lumbosacral spine segments were chosen to determine the safe anatomical area at which to operate. Finally, anterior transpedicle screws were inserted in L5 and S1 to determine the regularity of anterior pedicle screw insertion. Results We measured the anterior projection parameters, including the distances to the upper endplate (L5:12.5 ± 1.3 mm; S1: 4.54 ± 0.87 mm), lower endplate (L5: 17.3 ± 1.6 mm), and midline (L5: 6.6 ± 0.7 mm; S1: 6.6 ± 0.6 mm); the screw trajectory angle, including the transverse screw angle (L5: 25.3° ± 2.8°; S1: 25.7° ± 2.6°), sagittal screw angle (L5: 17.1° ± 1.7°; S1: 22.4° ± 1.1°); and the BSPL (L5: 48.6 ± 3.5 mm; S1: 48.0 ± 3.5 mm). We then identified the safe operating area and the regularity of L5 and S1 anterior pedicle screw insertions. Conclusions We determined the projection, screw trajectory angle, and BSPL of anterior transpedicle screws in L5 and S1, their insertion regularity, and the area in which the operation could be safely performed. |
