Category | Parameter | Definition |
---|---|---|
Local factor | Segmental angle [11] | Angle between the perpendicular line of the lower endplate of the upper vertebra and upper endplate of the lower vertebra |
Segmental translation [11] | Forward or backward slippage on a lateral radiograph | |
Lumbar factor | Short lumbar lordosis [5] | Cobb angle between the upper endplate of the fused vertebra and lower endplate of the fused vertebra |
Whole lumbar lordosis [5] | Cobb angle between the upper endplate of L1 and the lower endplate of L5 | |
Spinopelvic factor | Pelvic incidence [12] | Angle between the perpendicular line to the mid-point of the upper sacral endplate and mid-point of both femoral heads |
Pelvic tilt [12] | Angle between the vertical line from the femoral head and center of the sacral endplate | |
Sacral slope [12] | Angle between the vertical line and superior sacral endplate | |
Global sagittal balance | Thoracic kyphosis [12] | Angle between the T4 upper endplate and T12 lower endplate |
Sagittal vertical axis [12] | Distance from the vertical line of the C7 body to the inferior lateral corner of the L5 body | |
Sagittal balance [12] | Sagittal vertical axis line located within 5 cm | |
Implant failure | Subsidence [13] | Greater or equal to 2 mm loss of height |
Pseudoarthrosis [6] | Bony non-union between two vertebrae | |
Proximal junctional kyphosis [6] | Proximal junction Cobb angle of at least 10° greater than the preoperative angle | |
Screw malposition [6] | Perforated pedicular screw |