Fig 1.
Establishment of standard coordinate system for lumbar model.
(A) Establishment of the XY plane, YZ plane, and XZ plane; (B) Top view of the standard digital model; (C) Right view of the standard digital model; (D) Center point of the pedicle established by planes.
Fig 2.
Establishment of five key points for this approach.
(A) Determination of points P1 and C1; (B) Determination of points P2 and P3; (C) P4 is located in the color heaviest area of the transverse process; (D) The five points were projected onto a sketch.
Fig 3.
Measurement of TPA for the lumbar model and DR.
(A) Pedicle width of the lumbar model under AP view; (B) Pedicle length of the lumbar model under lateral view; (C) Pedicle width of the DR under AP view; (D) Pedicle length of the DR under lateral view, yellow indicates the top of the inferior vertebral notch.
Fig 4.
Schematic diagram of measurement length and TPA.
Table 1.
Baseline measurement data for the L3 vertebral body.
Table 2.
Baseline measurement data for the L4 vertebral body.
Table 3.
Baseline measurement data for the L5 vertebral body.
Table 4.
Differences between right and left for each measurement parameter.
Table 5.
Reliability analysis of TPA using independent t test.
Table 6.
Reliability analysis of DR-TPA using an independent t test.
Fig 5.
Simulated trajectory of screw placement by our approach in this manuscript (screw size:φ6.5 mm×4.5 cm).
(A) view left; (B) view top; (C) view back, transparency = 0.5; (D) view back, transparency = 0.