Table 1.

Basic data of patients and augmented screws

Clinical characteristics for the patient (n = 371)
Age (years)^a	66.29 ± 8.87
Sex
Male	54
Female	317
BMI^a	22.67 ± 3.32
BMD (T score)^a	− 3.27 ± 0.94
Diagnosis
Osteoporotic vertebral fractures	23
Lumbar spondylolisthesis	151
Degenerative scoliosis	77
Lumbar spinal stenosis	120
No. of fused segments per patient
Single segment	47
Double segments	164
Multiple segments	160
Blood loss (mL)^a	710.19 ± 575.66
Operative time (mins)^a	258.30 ± 61.31
Screw design
Solid	101
Fenestrated	270
Epidural cement leakage
No epidural leakage	301
Local epidural leakage	51
Extensive epidural leakage	19
Characteristics for the augmented screws (n = 1898)
The level of augmented screws
Thoracic segments (T10-T12)	47
Lumbar segments (L1-L5)	1851
Screw design
Solid	428
Fenestrated	1470
Epidural cement leakage
No epidural leakage	1754
Local epidural leakage	112
Extensive epidural leakage	32
The morphology of basivertebral foramen
A magistral type	801
A dispersed type	1097
The position of pedicle screw in the vertebral body (mm)^a
The distance between screw tip and the midline of vertebral body	24.10 ± 3.25
The distance between screw tip and the posterior wall of vertebral body	5.47 ± 2.38
Cement extension into pedicle area
Yes	110
No	1788

BMI body mass index, BMD bone mineral density

^aQuantitative variables are expressed as mean ± SD