Table 1.

PR, SAR and MSL comparisons in the different zoned trajectories

Entry point	0–1 mm	1–2 mm	2–3 mm	3–4 mm	4–5 mm	5–6 mm	6–7 mm
PR (%)	–	–	54	71	77	85	81
SA (deg)	–	–	68.31 ± 2.89 to 72.06 ± 2.37	66.36 ± 2.56 to 70.97 ± 1.84	55.97 ± 4.36 to 63.61 ± 3.11	49.68 ± 4.94 to 59.19 ± 4.70	47.05 ± 4.57 to 55.09 ± 4.37
SAR (deg)	–	–	3.74 ± 1.79	4.59 ± 1.71	7.62 ± 3.66	9.57 ± 4.36	8.03 ± 4.10
MSL (mm)	–	–	14.73 ± 1.30	15.28 ± 1.32	19.14 ± 2.57	21.74 ± 2.44	21.92 ± 2.37

Values are mean ± SD

PR pass ratio, SAR safe angle range, SA screw angle (in the axial plane), MSL screw length in the middle of safe angle