Table 1 Patient demographics

Number of patients (m/f)

8 (6/2)

117 (64/53)

125 (70/55)

Average age (years; mean ± SD)

62.2 ± 12.3

64.9 ± 10.3

66.8 ± 11.3

Average observation period (months)

25.5

24.8

25.2

Average fusion levels (mean ± SD)

1.4 ± 0.96*

1.1 ± 1.02

1.7 ± 0.98

Spondylolisthesis grade (Myerding)

Grade I

7

109

116

Grade II

1

8

9