Fig 1.
Measurement of lumbar lordosis angle (LLA) and sacral slope angle (SSA).
(A) First, lines were drawn tangential to the superior endplate of L1 and the inferior endplate of L5 on X-ray films. Second, perpendicular lines were drawn to each tangent. The LLA (α) was defined as the acute angle formed by the intersection of two perpendicular lines. (B) Lines were drawn tangential to the superior endplate of S1 and horizontal on the X-ray films. The SSA (β) was defined as the acute angle formed by the two lines.
Fig 2.
Measurement of spondylolysis fracture angle (SFA).
The SFA (α) was defined as the angle between the line parallel to the posterior cortex of the vertebral body (solid line) and fracture line (dotted line), with the direction of the spinous process being positive. (A) Bilateral spondylolysis. (B) Unilateral spondylolysis.
Fig 3.
Scatter plot of spondylolysis fracture angle (SFA) and lumbar lordosis angle (LLA) in bilateral spondylolysis (A) and unilateral spondylolysis (B). There was no significant correlation between SFA and LLA [bilateral (p = .072), unilateral (p = .76)].
Table 1.
Measured data for all spondylolysis and control group.
Table 2.
Measured data for all patient in each group.