Table 1.

Characteristics of patients

Characteristic	Value
Age (yr)	68±9.6
Sex
Male	21
Female	28
Diagnosis
Stenosis	41
Spinal instability	8
No. of spinal surgery
1	38
2	10
6	1
No. of fused segments
1	24
2	8
3	6
≥4	11

Values are presented as mean±standard deviation or number.